Mersenne prime
In mathematics, a Mersenne prime is a prime number that is one less than a power of two. That is, it is a prime number of the form M_{n} = 2^{n} − 1 for some integer n. They are named after Marin Mersenne, a French Minim friar, who studied them in the early 17th century.
Named after  Marin Mersenne 

Publication year  1536[1] 
Author of publication  Regius, H. 
No. of known terms  51 
Conjectured no. of terms  Infinite 
Subsequence of  Mersenne numbers 
First terms  3, 7, 31, 127 
Largest known term  2^{82,589,933} − 1 (December 7, 2018) 
OEIS index 

The exponents n which give Mersenne primes are 2, 3, 5, 7, 13, 17, 19, 31, ... (sequence A000043 in the OEIS) and the resulting Mersenne primes are 3, 7, 31, 127, 8191, 131071, 524287, 2147483647, ... (sequence A000668 in the OEIS).
If n is a composite number then so is 2^{n} − 1. (2^{ab} − 1 is divisible by both 2^{a} − 1 and 2^{b} − 1.) This definition is therefore equivalent to the definition as a prime number of the form M_{p} = 2^{p} − 1 for some prime p.
More generally, numbers of the form M_{n} = 2^{n} − 1 without the primality requirement may be called Mersenne numbers. Sometimes, however, Mersenne numbers are defined to have the additional requirement that n be prime. The smallest composite Mersenne number with prime exponent n is 2^{11} − 1 = 2047 = 23 × 89.
Mersenne primes M_{p} are also noteworthy due to their connection to perfect numbers.
As of June 2019, 51 Mersenne primes are known. The largest known prime number, 2^{82,589,933} − 1, is a Mersenne prime.[2] Since 1997, all newly found Mersenne primes have been discovered by the Great Internet Mersenne Prime Search (GIMPS), a distributed computing project on the Internet.
About Mersenne primes
Unsolved problem in mathematics: Are there infinitely many Mersenne primes? (more unsolved problems in mathematics) 
Many fundamental questions about Mersenne primes remain unresolved. It is not even known whether the set of Mersenne primes is finite or infinite. The Lenstra–Pomerance–Wagstaff conjecture asserts that there are infinitely many Mersenne primes and predicts their order of growth. It is also not known whether infinitely many Mersenne numbers with prime exponents are composite, although this would follow from widely believed conjectures about prime numbers, for example, the infinitude of Sophie Germain primes congruent to 3 (mod 4). For these primes p, 2p + 1 (which is also prime) will divide M_{p}, for example, 23  M_{11}, 47  M_{23}, 167  M_{83}, 263  M_{131}, 359  M_{179}, 383  M_{191}, 479  M_{239}, and 503  M_{251} (sequence A002515 in the OEIS). Since for these primes p, 2p + 1 is congruent to 7 mod 8, so 2 is a quadratic residue mod 2p + 1, and the multiplicative order of 2 mod 2p + 1 must divide = p. Since p is a prime, it must be p or 1. However, it cannot be 1 since and 1 has no prime factors, so it must be p. Hence, 2p + 1 divides and cannot be prime.
The first four Mersenne primes are M_{2} = 3, M_{3} = 7, M_{5} = 31 and M_{7} = 127 and because the first Mersenne prime starts at M_{2}, all Mersenne primes are congruent to 3 (mod 4). Other than M_{0} = 0 and M_{1} = 1, all other Mersenne numbers are also congruent to 3 (mod 4). Consequently, in the prime factorization of a Mersenne number ( ≥ M_{2} ) there must be at least one prime factor congruent to 3 (mod 4).
A basic theorem about Mersenne numbers states that if M_{p} is prime, then the exponent p must also be prime. This follows from the identity
This rules out primality for Mersenne numbers with composite exponent, such as M_{4} = 2^{4} − 1 = 15 = 3 × 5 = (2^{2} − 1) × (1 + 2^{2}).
Though the above examples might suggest that M_{p} is prime for all primes p, this is not the case, and the smallest counterexample is the Mersenne number
 M_{11} = 2^{11} − 1 = 2047 = 23 × 89.
The evidence at hand suggests that a randomly selected Mersenne number is much more likely to be prime than an arbitrary randomly selected odd integer of similar size.[3] Nonetheless, prime values of M_{p} appear to grow increasingly sparse as p increases. For example, eight of the first 11 primes p give rise to a Mersenne prime M_{p} (the correct terms on Mersenne's original list), while M_{p} is prime for only 43 of the first two million prime numbers (up to 32,452,843).
The lack of any simple test to determine whether a given Mersenne number is prime makes the search for Mersenne primes a difficult task, since Mersenne numbers grow very rapidly. The Lucas–Lehmer primality test (LLT) is an efficient primality test that greatly aids this task, making it much easier to test the primality of Mersenne numbers than that of most other numbers of the same size. The search for the largest known prime has somewhat of a cult following. Consequently, a lot of computer power has been expended searching for new Mersenne primes, much of which is now done using distributed computing.
Arithmetic modulo a Mersennne number is particularly efficient on a binary computer, making them popular choices when a prime modulus is desired, such as the Park–Miller random number generator. To find a primitive polynomial of Mersenne number order requires knowing the factorization of that number, so Mersenne primes allow one to find to primitive polynomials of very high order. Such primitive trinomials are used in pseudorandom number generators with very large periods such as the Mersenne twister, generalized shift register and Lagged Fibonacci generators.
Perfect numbers
Mersenne primes M_{p} are also noteworthy due to their connection with perfect numbers. In the 4th century BC, Euclid proved that if 2^{p} − 1 is prime, then 2^{p − 1}(2^{p} − 1) is a perfect number. This number, also expressible as M_{p}(M_{p} + 1)/2, is the M_{p}th triangular number and the 2^{p − 1}th hexagonal number. In the 18th century, Leonhard Euler proved that, conversely, all even perfect numbers have this form.[4] This is known as the Euclid–Euler theorem. It is unknown whether there are any odd perfect numbers.
History
2  3  5  7  11  13  17  19 

23  29  31  37  41  43  47  53 
59  61  67  71  73  79  83  89 
97  101  103  107  109  113  127  131 
137  139  149  151  157  163  167  173 
179  181  191  193  197  199  211  223 
227  229  233  239  241  251  257  263 
269  271  277  281  283  293  307  311 
The first 64 prime exponents with those corresponding to Mersenne primes shaded in cyan and in bold, and those thought to do so by Mersenne in red and bold. 
Mersenne primes take their name from the 17thcentury French scholar Marin Mersenne, who compiled what was supposed to be a list of Mersenne primes with exponents up to 257. The exponents listed by Mersenne were as follows:
 2, 3, 5, 7, 13, 17, 19, 31, 67, 127, 257.
His list replicated the known primes of his time with exponents up to 19. His next entry, 31, was correct, but the list then became largely incorrect, as Mersenne mistakenly included M_{67} and M_{257} (which are composite) and omitted M_{61}, M_{89}, and M_{107} (which are prime). Mersenne gave little indication how he came up with his list.[5]
Édouard Lucas proved in 1876 that M_{127} is indeed prime, as Mersenne claimed. This was the largest known prime number for 75 years, and the largest ever found by hand. M_{61} was determined to be prime in 1883 by Ivan Mikheevich Pervushin, though Mersenne claimed it was composite, and for this reason it is sometimes called Pervushin's number. This was the secondlargest known prime number, and it remained so until 1911. Lucas had shown another error in Mersenne's list in 1876. Without finding a factor, Lucas demonstrated that M_{67} is actually composite. No factor was found until a famous talk by Frank Nelson Cole in 1903.[6] Without speaking a word, he went to a blackboard and raised 2 to the 67th power, then subtracted one. On the other side of the board, he multiplied 193,707,721 × 761,838,257,287 and got the same number, then returned to his seat (to applause) without speaking.[7] He later said that the result had taken him "three years of Sundays" to find.[8] A correct list of all Mersenne primes in this number range was completed and rigorously verified only about three centuries after Mersenne published his list.
Searching for Mersenne primes
Fast algorithms for finding Mersenne primes are available, and as of June 2019 the seven largest known prime numbers are Mersenne primes.
The first four Mersenne primes M_{2} = 3, M_{3} = 7, M_{5} = 31 and M_{7} = 127 were known in antiquity. The fifth, M_{13} = 8191, was discovered anonymously before 1461; the next two (M_{17} and M_{19}) were found by Pietro Cataldi in 1588. After nearly two centuries, M_{31} was verified to be prime by Leonhard Euler in 1772. The next (in historical, not numerical order) was M_{127}, found by Édouard Lucas in 1876, then M_{61} by Ivan Mikheevich Pervushin in 1883. Two more (M_{89} and M_{107}) were found early in the 20th century, by R. E. Powers in 1911 and 1914, respectively.
The best method presently known for testing the primality of Mersenne numbers is the Lucas–Lehmer primality test. Specifically, it can be shown that for prime p > 2, M_{p} = 2^{p} − 1 is prime if and only if M_{p} divides S_{p − 2}, where S_{0} = 4 and S_{k} = (S_{k − 1})^{2} − 2 for k > 0.
During the era of manual calculation, all the exponents up to and including 257 were tested with the Lucas–Lehmer test and found to be composite. A notable contribution was made by retired Yale physics professor Horace Scudder Uhler, who did the calculations for exponents 157, 167, 193, 199, 227, and 229.[9] Unfortunately for those investigators, the interval they were testing contains the largest known relative gap between Mersenne primes; in relative terms: the next Mersenne prime exponent, 521, would turn out to be more than four times larger than the previous record of 127.
The search for Mersenne primes was revolutionized by the introduction of the electronic digital computer. Alan Turing searched for them on the Manchester Mark 1 in 1949,[10] but the first successful identification of a Mersenne prime, M_{521}, by this means was achieved at 10:00 pm on January 30, 1952 using the U.S. National Bureau of Standards Western Automatic Computer (SWAC) at the Institute for Numerical Analysis at the University of California, Los Angeles, under the direction of Lehmer, with a computer search program written and run by Prof. R. M. Robinson. It was the first Mersenne prime to be identified in thirtyeight years; the next one, M_{607}, was found by the computer a little less than two hours later. Three more — M_{1279}, M_{2203}, M_{2281} — were found by the same program in the next several months. M_{4253} is the first Mersenne prime that is titanic, M_{44,497} is the first gigantic, and M_{6,972,593} was the first megaprime to be discovered, being a prime with at least 1,000,000 digits.[11] All three were the first known prime of any kind of that size. The number of digits in the decimal representation of M_{n} equals ⌊n × log_{10}2⌋ + 1, where ⌊x⌋ denotes the floor function (or equivalently ⌊log_{10}M_{n}⌋ + 1).
In September 2008, mathematicians at UCLA participating in GIMPS won part of a $100,000 prize from the Electronic Frontier Foundation for their discovery of a very nearly 13milliondigit Mersenne prime. The prize, finally confirmed in October 2009, is for the first known prime with at least 10 million digits. The prime was found on a Dell OptiPlex 745 on August 23, 2008. This was the eighth Mersenne prime discovered at UCLA.[12]
On April 12, 2009, a GIMPS server log reported that a 47th Mersenne prime had possibly been found. The find was first noticed on June 4, 2009, and verified a week later. The prime is 2^{42,643,801} − 1. Although it is chronologically the 47th Mersenne prime to be discovered, it is smaller than the largest known at the time, which was the 45th to be discovered.
On January 25, 2013, Curtis Cooper, a mathematician at the University of Central Missouri, discovered a 48th Mersenne prime, 2^{57,885,161} − 1 (a number with 17,425,170 digits), as a result of a search executed by a GIMPS server network.[13]
On January 19, 2016, Cooper published his discovery of a 49th Mersenne prime, 2^{74,207,281} − 1 (a number with 22,338,618 digits), as a result of a search executed by a GIMPS server network.[14][15][16] This was the fourth Mersenne prime discovered by Cooper and his team in the past ten years.
On September 2, 2016, the Great Internet Mersenne Prime Search finished verifying all tests below M_{37,156,667}, thus officially confirming its position as the 45th Mersenne prime.[17]
On January 3, 2018, it was announced that Jonathan Pace, a 51yearold electrical engineer living in Germantown, Tennessee, had found a 50th Mersenne prime, 2^{77,232,917} − 1 (a number with 23,249,425 digits), as a result of a search executed by a GIMPS server network.[18]
On December 21, 2018, it was announced that The Great Internet Mersenne Prime Search (GIMPS) discovered the largest known prime number, 2^{82,589,933} − 1, having 24,862,048 digits. A computer volunteered by Patrick Laroche from Ocala, Florida made the find on December 7, 2018.[19]
Theorems about Mersenne numbers
 If a and p are natural numbers such that a^{p} − 1 is prime, then a = 2 or p = 1.
 Proof: a ≡ 1 (mod a − 1). Then a^{p} ≡ 1 (mod a − 1), so a^{p} − 1 ≡ 0 (mod a − 1). Thus a − 1  a^{p} − 1. However, a^{p} − 1 is prime, so a − 1 = a^{p} − 1 or a − 1 = ±1. In the former case, a = a^{p}, hence a = 0,1 (which is a contradiction, as neither −1 nor 0 is prime) or p = 1. In the latter case, a = 2 or a = 0. If a = 0, however, 0^{p} − 1 = 0 − 1 = −1 which is not prime. Therefore, a = 2.
 If 2^{p} − 1 is prime, then p is prime.
 Proof: suppose that p is composite, hence can be written p = ab with a and b > 1. Then 2^{p} − 1 = 2^{ab} − 1 = (2^{a})^{b} − 1 = (2^{a} − 1)((2^{a})^{b−1} + (2^{a})^{b−2} + … + 2^{a} + 1) so 2^{p} − 1 is composite. By contrapositive, if 2^{p} − 1 is prime then p is prime.
 If p is an odd prime, then every prime q that divides 2^{p} − 1 must be 1 plus a multiple of 2p. This holds even when 2^{p} − 1 is prime.
 For example, 2^{5} − 1 = 31 is prime, and 31 = 1 + 3 × (2 × 5). A composite example is 2^{11} − 1 = 23 × 89, where 23 = 1 + (2 × 11) and 89 = 1 + 4 × (2 × 11).
 Proof: By Fermat's little theorem, q is a factor of 2^{q−1} − 1. Since q is a factor of 2^{p} − 1, for all positive integers c, q is also a factor of 2^{pc} − 1. Since p is prime and q is not a factor of 2^{1} − 1, p is also the smallest positive integer x such that q is a factor of 2^{x} − 1. As a result, for all positive integers x, q is a factor of 2^{x} − 1 if and only if p is a factor of x. Therefore, since q is a factor of 2^{q−1} − 1, p is a factor of q − 1 so q ≡ 1 (mod p). Furthermore, since q is a factor of 2^{p} − 1, which is odd, q is odd. Therefore, q ≡ 1 (mod 2p).
 This fact leads to a proof of Euclid's theorem, which asserts the infinitude of primes, distinct from the proof written by Euclid: for every odd prime p, all primes dividing 2^{p} − 1 are larger than p; thus there are always larger primes than any particular prime.
 It follows from this fact that for every prime p > 2, there is at least one prime of the form 2kp+1 less than or equal to M_{p}, for some integer k.
 If p is an odd prime, then every prime q that divides 2^{p} − 1 is congruent to ±1 (mod 8).
 Proof: 2^{p+1} ≡ 2 (mod q), so 2^{1/2(p+1)} is a square root of 2 mod q. By quadratic reciprocity, every prime modulus in which the number 2 has a square root is congruent to ±1 (mod 8).
 A Mersenne prime cannot be a Wieferich prime.
 Proof: We show if p = 2^{m} − 1 is a Mersenne prime, then the congruence 2^{p−1} ≡ 1 (mod p^{2}) does not hold. By Fermat's little theorem, m  p − 1. Therefore, one can write p − 1 = mλ. If the given congruence is satisfied, then p^{2}  2^{mλ} − 1, therefore 0 ≡ 2^{mλ} − 1/2^{m} − 1 = 1 + 2^{m} + 2^{2m} + ... + 2^{(λ − 1)m} ≡ −λ mod (2^{m} − 1). Hence 2^{m} − 1  λ, and therefore λ ≥ 2^{m} − 1. This leads to p − 1 ≥ m(2^{m} − 1), which is impossible since m ≥ 2.
 If m and n are natural numbers then m and n are coprime if and only if 2^{m} − 1 and 2^{n} − 1 are coprime. Consequently, a prime number divides at most one primeexponent Mersenne number,[20] so in other words the set of pernicious Mersenne numbers is pairwise coprime.
 If p and 2p + 1 are both prime (meaning that p is a Sophie Germain prime), and p is congruent to 3 (mod 4), then 2p + 1 divides 2^{p} − 1.[21]
 Example: 11 and 23 are both prime, and 11 = 2 × 4 + 3, so 23 divides 2^{11} − 1.
 Proof: Let q be 2p + 1. By Fermat's little theorem, 2^{2p} ≡ 1 (mod q), so either 2^{p} ≡ 1 (mod q) or 2^{p} ≡ −1 (mod q). Supposing latter true, then 2^{p+1} = (2^{1/2(p + 1)})^{2} ≡ −2 (mod q), so −2 would be a quadratic residue mod q. However, since p is congruent to 3 (mod 4), q is congruent to 7 (mod 8) and therefore 2 is a quadratic residue mod q. Also since q is congruent to 3 (mod 4), −1 is a quadratic nonresidue mod q, so −2 is the product of a residue and a nonresidue and hence it is a nonresidue, which is a contradiction. Hence, the former congruence must be true and 2p + 1 divides M_{p}.
 All composite divisors of primeexponent Mersenne numbers are strong pseudoprimes to the base 2.
 With the exception of 1, a Mersenne number cannot be a perfect power. In other words, and in accordance with Mihăilescu's theorem, the equation 2^{m} − 1 = n^{k} has no solutions where m, n, and k are integers with m > 1 and k > 1.
List of known Mersenne primes
The table below lists all known Mersenne primes (sequence A000043 (p) and A000668 (M_{p}) in OEIS):
#  p  M_{p}  M_{p} digits  Discovered  Discoverer  Method used 

1  2  3  1  c. 430 BC  Ancient Greek mathematicians[22]  
2  3  7  1  c. 430 BC  Ancient Greek mathematicians[22]  
3  5  31  2  c. 300 BC  Ancient Greek mathematicians[23]  
4  7  127  3  c. 300 BC  Ancient Greek mathematicians[23]  
5  13  8191  4  1456  Anonymous[24][25]  Trial division 
6  17  131071  6  1588[26]  Pietro Cataldi  Trial division[27] 
7  19  524287  6  1588  Pietro Cataldi  Trial division[28] 
8  31  2147483647  10  1772  Leonhard Euler[29][30]  Trial division with modular restrictions[31] 
9  61  2305843009213693951  19  1883 November[32]  Ivan M. Pervushin  Lucas sequences 
10  89  618970019642...137449562111  27  1911 June[33]  Ralph Ernest Powers  Lucas sequences 
11  107  162259276829...578010288127  33  1914 June 1[34][35][36]  Ralph Ernest Powers[37]  Lucas sequences 
12  127  170141183460...715884105727  39  1876 January 10[38]  Édouard Lucas  Lucas sequences 
13  521  686479766013...291115057151  157  1952 January 30[39]  Raphael M. Robinson  LLT / SWAC 
14  607  531137992816...219031728127  183  1952 January 30[39]  Raphael M. Robinson  LLT / SWAC 
15  1,279  104079321946...703168729087  386  1952 June 25[40]  Raphael M. Robinson  LLT / SWAC 
16  2,203  147597991521...686697771007  664  1952 October 7[41]  Raphael M. Robinson  LLT / SWAC 
17  2,281  446087557183...418132836351  687  1952 October 9[41]  Raphael M. Robinson  LLT / SWAC 
18  3,217  259117086013...362909315071  969  1957 September 8[42]  Hans Riesel  LLT / BESK 
19  4,253  190797007524...815350484991  1,281  1961 November 3[43][44]  Alexander Hurwitz  LLT / IBM 7090 
20  4,423  285542542228...902608580607  1,332  1961 November 3[43][44]  Alexander Hurwitz  LLT / IBM 7090 
21  9,689  478220278805...826225754111  2,917  1963 May 11[45]  Donald B. Gillies  LLT / ILLIAC II 
22  9,941  346088282490...883789463551  2,993  1963 May 16[45]  Donald B. Gillies  LLT / ILLIAC II 
23  11,213  281411201369...087696392191  3,376  1963 June 2[45]  Donald B. Gillies  LLT / ILLIAC II 
24  19,937  431542479738...030968041471  6,002  1971 March 4[46]  Bryant Tuckerman  LLT / IBM 360/91 
25  21,701  448679166119...353511882751  6,533  1978 October 30[47]  Landon Curt Noll & Laura Nickel  LLT / CDC Cyber 174 
26  23,209  402874115778...523779264511  6,987  1979 February 9[48]  Landon Curt Noll  LLT / CDC Cyber 174 
27  44,497  854509824303...961011228671  13,395  1979 April 8[49][50]  Harry L. Nelson & David Slowinski  LLT / Cray 1 
28  86,243  536927995502...709433438207  25,962  1982 September 25  David Slowinski  LLT / Cray 1 
29  110,503  521928313341...083465515007  33,265  1988 January 29[51][52]  Walter Colquitt & Luke Welsh  LLT / NEC SX2[53] 
30  132,049  512740276269...455730061311  39,751  1983 September 19[54]  David Slowinski  LLT / Cray XMP 
31  216,091  746093103064...103815528447  65,050  1985 September 1[55][56]  David Slowinski  LLT / Cray XMP/24 
32  756,839  174135906820...328544677887  227,832  1992 February 17  David Slowinski & Paul Gage  LLT / Harwell Lab's Cray2[57] 
33  859,433  129498125604...243500142591  258,716  1994 January 4[58][59][60]  David Slowinski & Paul Gage  LLT / Cray C90 
34  1,257,787  412245773621...976089366527  378,632  1996 September 3[61]  David Slowinski & Paul Gage[62]  LLT / Cray T94 
35  1,398,269  814717564412...868451315711  420,921  1996 November 13  GIMPS / Joel Armengaud[63]  LLT / Prime95 on 90 MHz Pentium 
36  2,976,221  623340076248...743729201151  895,932  1997 August 24  GIMPS / Gordon Spence[64]  LLT / Prime95 on 100 MHz Pentium 
37  3,021,377  127411683030...973024694271  909,526  1998 January 27  GIMPS / Roland Clarkson[65]  LLT / Prime95 on 200 MHz Pentium 
38  6,972,593  437075744127...142924193791  2,098,960  1999 June 1  GIMPS / Nayan Hajratwala[66]  LLT / Prime95 on 350 MHz Pentium II IBM Aptiva 
39  13,466,917  924947738006...470256259071  4,053,946  2001 November 14  GIMPS / Michael Cameron[67]  LLT / Prime95 on 800 MHz Athlon TBird 
40  20,996,011  125976895450...762855682047  6,320,430  2003 November 17  GIMPS / Michael Shafer[68]  LLT / Prime95 on 2 GHz Dell Dimension 
41  24,036,583  299410429404...882733969407  7,235,733  2004 May 15  GIMPS / Josh Findley[69]  LLT / Prime95 on 2.4 GHz Pentium 4 
42  25,964,951  122164630061...280577077247  7,816,230  2005 February 18  GIMPS / Martin Nowak[70]  LLT / Prime95 on 2.4 GHz Pentium 4 
43  30,402,457  315416475618...411652943871  9,152,052  2005 December 15  GIMPS / Curtis Cooper & Steven Boone[71]  LLT / Prime95 on 2 GHz Pentium 4 
44  32,582,657  124575026015...154053967871  9,808,358  2006 September 4  GIMPS / Curtis Cooper & Steven Boone[72]  LLT / Prime95 on 3 GHz Pentium 4 
45  37,156,667  202254406890...022308220927  11,185,272  2008 September 6  GIMPS / HansMichael Elvenich[73]  LLT / Prime95 on 2.83 GHz Core 2 Duo 
46  42,643,801  169873516452...765562314751  12,837,064  2009 June 4[n 1]  GIMPS / Odd M. Strindmo[74][n 2]  LLT / Prime95 on 3 GHz Core 2 
47  43,112,609  316470269330...166697152511  12,978,189  2008 August 23  GIMPS / Edson Smith[73]  LLT / Prime95 on Dell Optiplex 745 
48[n 3]  57,885,161  581887266232...071724285951  17,425,170  2013 January 25  GIMPS / Curtis Cooper[75]  LLT / Prime95 on 3 GHz Intel Core2 Duo E8400[76] 
49[n 3]  74,207,281  300376418084...391086436351  22,338,618  2016 January 7[n 4]  GIMPS / Curtis Cooper[14]  LLT / Prime95 on Intel Core i74790 
50[n 3]  77,232,917  467333183359...069762179071  23,249,425  2017 December 26  GIMPS / Jon Pace[77]  LLT / Prime95 on 3.3 GHz Intel Core i56600[78] 
51[n 3]  82,589,933  148894445742...325217902591  24,862,048  2018 December 7  GIMPS / Patrick Laroche[2]  LLT / Prime95 on Intel Core i54590T 
 Although M_{42,643,801} was first reported by a machine on April 12, 2009, no human took notice of this fact until June 4, 2009.
 Strindmo also uses the alias Stig M. Valstad.
 It is not verified whether any undiscovered Mersenne primes exist between the 47th (M_{43,112,609}) and the 51st (M_{82,589,933}) on this chart; the ranking is therefore provisional.
 Although M_{74,207,281} was first reported by a machine on September 17, 2015, no human took notice of this fact until January 7, 2016.
All Mersenne numbers below the 51st Mersenne prime (M_{82,589,933}) have been tested at least once but some have not been doublechecked. Primes are not always discovered in increasing order. For example, the 29th Mersenne prime was discovered after the 30th and the 31st. Similarly, M_{43,112,609} was followed by two smaller Mersenne primes, first 2 weeks later and then 9 months later.[79] M_{43,112,609} was the first discovered prime number with more than 10 million decimal digits.
The largest known Mersenne prime (2^{82,589,933} − 1) is also the largest known prime number.[2]
The largest known prime has been a Mersenne prime since 1952, except between 1989 and 1992.[80]
Factorization of composite Mersenne numbers
Since they are prime numbers, Mersenne primes are divisible only by 1 and by themselves. However, not all Mersenne numbers are Mersenne primes, and the composite Mersenne numbers may be factored nontrivially. Mersenne numbers are very good test cases for the special number field sieve algorithm, so often the largest number factorized with this algorithm has been a Mersenne number. As of June 2019, 2^{1,193} − 1 is the recordholder,[81] having been factored with a variant of the special number field sieve that allows the factorization of several numbers at once. See integer factorization records for links to more information. The special number field sieve can factorize numbers with more than one large factor. If a number has only one very large factor then other algorithms can factorize larger numbers by first finding small factors and then making a primality test on the cofactor. As of June 2019, the largest factorization with probable prime factors allowed is 2^{7,313,983} − 1 = 305,492,080,276,193 × q, where q is a 2,201,714digit probable prime. It was discovered by Oliver Kruse.[82] As of June 2019, the Mersenne number M_{1277} is the smallest composite Mersenne number with no known factors; it has no prime factors below 2^{67}.[83]
The table below shows factorizations for the first 20 composite Mersenne numbers (sequence A244453 in the OEIS).
p  M_{p}  Factorization of M_{p} 

11  2047  23 × 89 
23  8388607  47 × 178,481 
29  536870911  233 × 1,103 × 2,089 
37  137438953471  223 × 616,318,177 
41  2199023255551  13,367 × 164,511,353 
43  8796093022207  431 × 9,719 × 2,099,863 
47  140737488355327  2,351 × 4,513 × 13,264,529 
53  9007199254740991  6,361 × 69,431 × 20,394,401 
59  57646075230343487  179,951 × 3,203,431,780,337 (13 digits) 
67  147573952589676412927  193,707,721 × 761,838,257,287 (12 digits) 
71  2361183241434822606847  228,479 × 48,544,121 × 212,885,833 
73  9444732965739290427391  439 × 2,298,041 × 9,361,973,132,609 (13 digits) 
79  604462903807314587353087  2,687 × 202,029,703 × 1,113,491,139,767 (13 digits) 
83  967140655691...033397649407  167 × 57,912,614,113,275,649,087,721 (23 digits) 
97  158456325028...187087900671  11,447 × 13,842,607,235,828,485,645,766,393 (26 digits) 
101  253530120045...993406410751  7,432,339,208,719 (13 digits) × 341,117,531,003,194,129 (18 digits) 
103  101412048018...973625643007  2,550,183,799 × 3,976,656,429,941,438,590,393 (22 digits) 
109  649037107316...312041152511  745,988,807 × 870,035,986,098,720,987,332,873 (24 digits) 
113  103845937170...992658440191  3,391 × 23,279 × 65,993 × 1,868,569 × 1,066,818,132,868,207 (16 digits) 
131  272225893536...454145691647  263 × 10,350,794,431,055,162,386,718,619,237,468,234,569 (38 digits) 
The number of factors for the first 500 Mersenne numbers can be found at (sequence A046800 in the OEIS).
Mersenne numbers in nature and elsewhere
In the mathematical problem Tower of Hanoi, solving a puzzle with an ndisc tower requires M_{n} steps, assuming no mistakes are made.[84] The number of rice grains on the whole chessboard in the wheat and chessboard problem is M_{64}.
The asteroid with minor planet number 8191 is named 8191 Mersenne after Marin Mersenne, because 8191 is a Mersenne prime (3 Juno, 7 Iris, 31 Euphrosyne and 127 Johanna having been discovered and named during the 19th century).[85]
In geometry, an integer right triangle that is primitive and has its even leg a power of 2 ( ≥ 4 ) generates a unique right triangle such that its inradius is always a Mersenne number. For example, if the even leg is 2^{n + 1} then because it is primitive it constrains the odd leg to be 4^{n} − 1, the hypotenuse to be 4^{n} + 1 and its inradius to be 2^{n} − 1.[86]
The Mersenne numbers were studied with respect to the total number of accepting paths of nondeterministic polynomial time Turing machines in 2018[87] and intriguing inclusions were discovered.
Mersenne–Fermat primes
A Mersenne–Fermat number is defined as 2^{pr} − 1/2^{pr − 1} − 1, with p prime, r natural number, and can be written as MF(p, r), when r = 1, it is a Mersenne number, and when p = 2, it is a Fermat number, the only known Mersenne–Fermat prime with r > 1 are
 MF(2, 2), MF(3, 2), MF(7, 2), MF(59, 2), MF(2, 3), MF(3, 3), MF(2, 4), and MF(2, 5).[88]
In fact, MF(p, r) = Φ_{pr}(2), where Φ is the cyclotomic polynomial.
Generalizations
The simplest generalized Mersenne primes are prime numbers of the form f(2^{n}), where f(x) is a lowdegree polynomial with small integer coefficients.[89] An example is 2^{64} − 2^{32} + 1, in this case, n = 32, and f(x) = x^{2} − x + 1; another example is 2^{192} − 2^{64} − 1, in this case, n = 64, and f(x) = x^{3} − x − 1.
It is also natural to try to generalize primes of the form 2^{n} − 1 to primes of the form b^{n} − 1 (for b ≠ 2 and n > 1). However (see also theorems above), b^{n} − 1 is always divisible by b − 1, so unless the latter is a unit, the former is not a prime. This can be remedied by allowing b to be an algebraic integer instead of an integer:
Complex numbers
In the ring of integers (on real numbers), if b − 1 is a unit, then b is either 2 or 0. But 2^{n} − 1 are the usual Mersenne primes, and the formula 0^{n} − 1 does not lead to anything interesting (since it is always −1 for all n > 0). Thus, we can regard a ring of "integers" on complex numbers instead of real numbers, like Gaussian integers and Eisenstein integers.
Gaussian Mersenne primes
If we regard the ring of Gaussian integers, we get the case b = 1 + i and b = 1 − i, and can ask (WLOG) for which n the number (1 + i)^{n} − 1 is a Gaussian prime which will then be called a Gaussian Mersenne prime.[90]
(1 + i)^{n} − 1 is a Gaussian prime for the following n:
 2, 3, 5, 7, 11, 19, 29, 47, 73, 79, 113, 151, 157, 163, 167, 239, 241, 283, 353, 367, 379, 457, 997, 1367, 3041, 10141, 14699, 27529, 49207, 77291, 85237, 106693, 160423, 203789, 364289, 991961, 1203793, 1667321, 3704053, 4792057, ... (sequence A057429 in the OEIS)
Like the sequence of exponents for usual Mersenne primes, this sequence contains only (rational) prime numbers.
As for all Gaussian primes, the norms (that is, squares of absolute values) of these numbers are rational primes:
Eisenstein Mersenne primes
We can also regard the ring of Eisenstein integers, we get the case b = 1 + ω and b = 1 − ω, and can ask for what n the number (1 + ω)^{n} − 1 is an Eisenstein prime which will then be called a Eisenstein Mersenne prime.
(1 + ω)^{n} − 1 is an Eisenstein prime for the following n:
 2, 5, 7, 11, 17, 19, 79, 163, 193, 239, 317, 353, 659, 709, 1049, 1103, 1759, 2029, 5153, 7541, 9049, 10453, 23743, 255361, 534827, 2237561, ... (sequence A066408 in the OEIS)
The norms (that is, squares of absolute values) of these Eisenstein primes are rational primes:
Divide an integer
Repunit primes
The other way to deal with the fact that b^{n} − 1 is always divisible by b − 1, it is to simply take out this factor and ask which values of n make
be prime. (The integer b can be either positive or negative.) If, for example, we take b = 10, we get n values of:
 2, 19, 23, 317, 1031, 49081, 86453, 109297, 270343, ... (sequence A004023 in the OEIS),
corresponding to primes 11, 1111111111111111111, 11111111111111111111111, ... (sequence A004022 in the OEIS).
These primes are called repunit primes. Another example is when we take b = −12, we get n values of:
 2, 5, 11, 109, 193, 1483, 11353, 21419, 21911, 24071, 106859, 139739, ... (sequence A057178 in the OEIS),
corresponding to primes −11, 19141, 57154490053, ....
It is a conjecture that for every integer b which is not a perfect power, there are infinitely many values of n such that b^{n} − 1/b − 1 is prime. (When b is a perfect power, it can be shown that there is at most one n value such that b^{n} − 1/b − 1 is prime)
Least n such that b^{n} − 1/b − 1 is prime are (starting with b = 2, 0 if no such n exists)
 2, 3, 2, 3, 2, 5, 3, 0, 2, 17, 2, 5, 3, 3, 2, 3, 2, 19, 3, 3, 2, 5, 3, 0, 7, 3, 2, 5, 2, 7, 0, 3, 13, 313, 2, 13, 3, 349, 2, 3, 2, 5, 5, 19, 2, 127, 19, 0, 3, 4229, 2, 11, 3, 17, 7, 3, 2, 3, 2, 7, 3, 5, 0, 19, 2, 19, 5, 3, 2, 3, 2, ... (sequence A084740 in the OEIS)
For negative bases b, they are (starting with b = −2, 0 if no such n exists)
 3, 2, 2, 5, 2, 3, 2, 3, 5, 5, 2, 3, 2, 3, 3, 7, 2, 17, 2, 3, 3, 11, 2, 3, 11, 0, 3, 7, 2, 109, 2, 5, 3, 11, 31, 5, 2, 3, 53, 17, 2, 5, 2, 103, 7, 5, 2, 7, 1153, 3, 7, 21943, 2, 3, 37, 53, 3, 17, 2, 7, 2, 3, 0, 19, 7, 3, 2, 11, 3, 5, 2, ... (sequence A084742 in the OEIS) (notice this OEIS sequence does not allow n = 2)
Least base b such that b^{prime(n)} − 1/b − 1 is prime are
 2, 2, 2, 2, 5, 2, 2, 2, 10, 6, 2, 61, 14, 15, 5, 24, 19, 2, 46, 3, 11, 22, 41, 2, 12, 22, 3, 2, 12, 86, 2, 7, 13, 11, 5, 29, 56, 30, 44, 60, 304, 5, 74, 118, 33, 156, 46, 183, 72, 606, 602, 223, 115, 37, 52, 104, 41, 6, 338, 217, ... (sequence A066180 in the OEIS)
For negative bases b, they are
Other generalized Mersenne primes
Another generalized Mersenne number is
with a, b any coprime integers, a > 1 and −a < b < a. (Since a^{n} − b^{n} is always divisible by a − b, the division is necessary for there to be any chance of finding prime numbers. In fact, this number is the same as the Lucas number U_{n}(a + b, ab), since a and b are the roots of the quadratic equation x^{2} − (a + b)x + ab = 0, and this number equals 1 when n = 1) We can ask which n makes this number prime. It can be shown that such n must be primes themselves or equal to 4, and n can be 4 if and only if a + b = 1 and a^{2} + b^{2} is prime. (Since a^{4} − b^{4}/a − b = (a + b)(a^{2} + b^{2}). Thus, in this case the pair (a, b) must be (x + 1, −x) and x^{2} + (x + 1)^{2} must be prime. That is, x must be in OEIS: A027861.) It is a conjecture that for any pair (a, b) such that for every natural number r > 1, a and b are not both perfect rth powers, and −4ab is not a perfect fourth power. there are infinitely many values of n such that a^{n} − b^{n}/a − b is prime. (When a and b are both perfect rth powers for an r > 1 or when −4ab is a perfect fourth power, it can be shown that there are at most two n values with this property, since if so, then a^{n} − b^{n}/a − b can be factored algebraically) However, this has not been proved for any single value of (a, b).
a  b  numbers n such that a^{n} − b^{n}/a − b is prime (some large terms are only probable primes, these n are checked up to 100000 for b ≤ 5 or b = a − 1, 20000 for 5 < b < a − 1) 
OEIS sequence 

2  1  2, 3, 5, 7, 13, 17, 19, 31, 61, 89, 107, 127, 521, 607, 1279, 2203, 2281, 3217, 4253, 4423, 9689, 9941, 11213, 19937, 21701, 23209, 44497, 86243, 110503, 132049, 216091, 756839, 859433, 1257787, 1398269, 2976221, 3021377, 6972593, 13466917, 20996011, 24036583, 25964951, 30402457, 32582657, 37156667, 42643801, 43112609, ..., 57885161, ..., 74207281, ..., 77232917, ..., 82589933, ...  A000043 
2  −1  3, 4^{*}, 5, 7, 11, 13, 17, 19, 23, 31, 43, 61, 79, 101, 127, 167, 191, 199, 313, 347, 701, 1709, 2617, 3539, 5807, 10501, 10691, 11279, 12391, 14479, 42737, 83339, 95369, 117239, 127031, 138937, 141079, 267017, 269987, 374321, 986191, 4031399, ..., 13347311, 13372531, ...  A000978 
3  2  2, 3, 5, 17, 29, 31, 53, 59, 101, 277, 647, 1061, 2381, 2833, 3613, 3853, 3929, 5297, 7417, 90217, 122219, 173191, 256199, 336353, 485977, 591827, 1059503, ...  A057468 
3  1  3, 7, 13, 71, 103, 541, 1091, 1367, 1627, 4177, 9011, 9551, 36913, 43063, 49681, 57917, 483611, 877843, ...  A028491 
3  −1  2^{*}, 3, 5, 7, 13, 23, 43, 281, 359, 487, 577, 1579, 1663, 1741, 3191, 9209, 11257, 12743, 13093, 17027, 26633, 104243, 134227, 152287, 700897, 1205459, ...  A007658 
3  −2  3, 4^{*}, 7, 11, 83, 149, 223, 599, 647, 1373, 8423, 149497, 388897, ...  A057469 
4  3  2, 3, 7, 17, 59, 283, 311, 383, 499, 521, 541, 599, 1193, 1993, 2671, 7547, 24019, 46301, 48121, 68597, 91283, 131497, 148663, 184463, 341233, ...  A059801 
4  1  2 (no others)  
4  −1  2^{*}, 3 (no others)  
4  −3  3, 5, 19, 37, 173, 211, 227, 619, 977, 1237, 2437, 5741, 13463, 23929, 81223, 121271, ...  A128066 
5  4  3, 43, 59, 191, 223, 349, 563, 709, 743, 1663, 5471, 17707, 19609, 35449, 36697, 45259, 91493, 246497, 265007, 289937, ...  A059802 
5  3  13, 19, 23, 31, 47, 127, 223, 281, 2083, 5281, 7411, 7433, 19051, 27239, 35863, 70327, ...  A121877 
5  2  2, 5, 7, 13, 19, 37, 59, 67, 79, 307, 331, 599, 1301, 12263, 12589, 18443, 20149, 27983, ...  A082182 
5  1  3, 7, 11, 13, 47, 127, 149, 181, 619, 929, 3407, 10949, 13241, 13873, 16519, 201359, 396413, 1888279, ...  A004061 
5  −1  5, 67, 101, 103, 229, 347, 4013, 23297, 30133, 177337, 193939, 266863, 277183, 335429, ...  A057171 
5  −2  2^{*}, 3, 17, 19, 47, 101, 1709, 2539, 5591, 6037, 8011, 19373, 26489, 27427, ...  A082387 
5  −3  2^{*}, 3, 5, 7, 17, 19, 109, 509, 661, 709, 1231, 12889, 13043, 26723, 43963, 44789, ...  A122853 
5  −4  4^{*}, 5, 7, 19, 29, 61, 137, 883, 1381, 1823, 5227, 25561, 29537, 300893, ...  A128335 
6  5  2, 5, 11, 13, 23, 61, 83, 421, 1039, 1511, 31237, 60413, 113177, 135647, 258413, ...  A062572 
6  1  2, 3, 7, 29, 71, 127, 271, 509, 1049, 6389, 6883, 10613, 19889, 79987, 608099, ...  A004062 
6  −1  2^{*}, 3, 11, 31, 43, 47, 59, 107, 811, 2819, 4817, 9601, 33581, 38447, 41341, 131891, 196337, ...  A057172 
6  −5  3, 4^{*}, 5, 17, 397, 409, 643, 1783, 2617, 4583, 8783, ...  A128336 
7  6  2, 3, 7, 29, 41, 67, 1327, 1399, 2027, 69371, 86689, 355039, ...  A062573 
7  5  3, 5, 7, 113, 397, 577, 7573, 14561, 58543, ...  A128344 
7  4  2, 5, 11, 61, 619, 2879, 2957, 24371, 69247, ...  A213073 
7  3  3, 7, 19, 109, 131, 607, 863, 2917, 5923, 12421, ...  A128024 
7  2  3, 7, 19, 79, 431, 1373, 1801, 2897, 46997, ...  A215487 
7  1  5, 13, 131, 149, 1699, 14221, 35201, 126037, 371669, 1264699, ...  A004063 
7  −1  3, 17, 23, 29, 47, 61, 1619, 18251, 106187, 201653, ...  A057173 
7  −2  2^{*}, 5, 23, 73, 101, 401, 419, 457, 811, 1163, 1511, 8011, ...  A125955 
7  −3  3, 13, 31, 313, 3709, 7933, 14797, 30689, 38333, ...  A128067 
7  −4  2^{*}, 3, 5, 19, 41, 47, 8231, 33931, 43781, 50833, 53719, 67211, ...  A218373 
7  −5  2^{*}, 11, 31, 173, 271, 547, 1823, 2111, 5519, 7793, 22963, 41077, 49739, ...  A128337 
7  −6  3, 53, 83, 487, 743, ...  A187805 
8  7  7, 11, 17, 29, 31, 79, 113, 131, 139, 4357, 44029, 76213, 83663, 173687, 336419, 615997, ...  A062574 
8  5  2, 19, 1021, 5077, 34031, 46099, 65707, ...  A128345 
8  3  2, 3, 7, 19, 31, 67, 89, 9227, 43891, ...  A128025 
8  1  3 (no others)  
8  −1  2^{*} (no others)  
8  −3  2^{*}, 5, 163, 191, 229, 271, 733, 21059, 25237, ...  A128068 
8  −5  2^{*}, 7, 19, 167, 173, 223, 281, 21647, ...  A128338 
8  −7  4^{*}, 7, 13, 31, 43, 269, 353, 383, 619, 829, 877, 4957, 5711, 8317, 21739, 24029, 38299, ...  A181141 
9  8  2, 7, 29, 31, 67, 149, 401, 2531, 19913, 30773, 53857, 170099, ...  A059803 
9  7  3, 5, 7, 4703, 30113, ...  A273010 
9  5  3, 11, 17, 173, 839, 971, 40867, 45821, ...  A128346 
9  4  2 (no others)  
9  2  2, 3, 5, 13, 29, 37, 1021, 1399, 2137, 4493, 5521, ...  A173718 
9  1  (none)  
9  −1  3, 59, 223, 547, 773, 1009, 1823, 3803, 49223, 193247, 703393, ...  A057175 
9  −2  2^{*}, 3, 7, 127, 283, 883, 1523, 4001, ...  A125956 
9  −4  2^{*}, 3, 5, 7, 11, 17, 19, 41, 53, 109, 167, 2207, 3623, 5059, 5471, 7949, 21211, 32993, 60251, ...  A211409 
9  −5  3, 5, 13, 17, 43, 127, 229, 277, 6043, 11131, 11821, ...  A128339 
9  −7  2^{*}, 3, 107, 197, 2843, 3571, 4451, ..., 31517, ...  A301369 
9  −8  3, 7, 13, 19, 307, 619, 2089, 7297, 75571, 76103, 98897, ...  A187819 
10  9  2, 3, 7, 11, 19, 29, 401, 709, 2531, 15787, 66949, 282493, ...  A062576 
10  7  2, 31, 103, 617, 10253, 10691, ...  A273403 
10  3  2, 3, 5, 37, 599, 38393, 51431, ...  A128026 
10  1  2, 19, 23, 317, 1031, 49081, 86453, 109297, 270343, ...  A004023 
10  −1  5, 7, 19, 31, 53, 67, 293, 641, 2137, 3011, 268207, ...  A001562 
10  −3  2^{*}, 3, 19, 31, 101, 139, 167, 1097, 43151, 60703, 90499, ...  A128069 
10  −7  2^{*}, 3, 5, 11, 19, 1259, 1399, 2539, 2843, 5857, 10589, ...  
10  −9  4^{*}, 7, 67, 73, 1091, 1483, 10937, ...  A217095 
11  10  3, 5, 19, 311, 317, 1129, 4253, 7699, 18199, 35153, 206081, ...  A062577 
11  9  5, 31, 271, 929, 2789, 4153, ...  A273601 
11  8  2, 7, 11, 17, 37, 521, 877, 2423, ...  A273600 
11  7  5, 19, 67, 107, 593, 757, 1801, 2243, 2383, 6043, 10181, 11383, 15629, ...  A273599 
11  6  2, 3, 11, 163, 191, 269, 1381, 1493, ...  A273598 
11  5  5, 41, 149, 229, 263, 739, 3457, 20269, 98221, ...  A128347 
11  4  3, 5, 11, 17, 71, 89, 827, 22307, 45893, 63521, ...  A216181 
11  3  3, 5, 19, 31, 367, 389, 431, 2179, 10667, 13103, 90397, ...  A128027 
11  2  2, 5, 11, 13, 331, 599, 18839, 23747, 24371, 29339, 32141, 67421, ...  A210506 
11  1  17, 19, 73, 139, 907, 1907, 2029, 4801, 5153, 10867, 20161, 293831, ...  A005808 
11  −1  5, 7, 179, 229, 439, 557, 6113, 223999, 327001, ...  A057177 
11  −2  3, 5, 17, 67, 83, 101, 1373, 6101, 12119, 61781, ...  A125957 
11  −3  3, 103, 271, 523, 23087, 69833, ...  A128070 
11  −4  2^{*}, 7, 53, 67, 71, 443, 26497, ...  A224501 
11  −5  7, 11, 181, 421, 2297, 2797, 4129, 4139, 7151, 29033, ...  A128340 
11  −6  2^{*}, 5, 7, 107, 383, 17359, 21929, 26393, ...  
11  −7  7, 1163, 4007, 10159, ...  
11  −8  2^{*}, 3, 13, 31, 59, 131, 223, 227, 1523, ...  
11  −9  2^{*}, 3, 17, 41, 43, 59, 83, ...  
11  −10  53, 421, 647, 1601, 35527, ...  A185239 
12  11  2, 3, 7, 89, 101, 293, 4463, 70067, ...  A062578 
12  7  2, 3, 7, 13, 47, 89, 139, 523, 1051, ...  A273814 
12  5  2, 3, 31, 41, 53, 101, 421, 1259, 4721, 45259, ...  A128348 
12  1  2, 3, 5, 19, 97, 109, 317, 353, 701, 9739, 14951, 37573, 46889, 769543, ...  A004064 
12  −1  2^{*}, 5, 11, 109, 193, 1483, 11353, 21419, 21911, 24071, 106859, 139739, ...  A057178 
12  −5  2^{*}, 3, 5, 13, 347, 977, 1091, 4861, 4967, 34679, ...  A128341 
12  −7  2^{*}, 3, 7, 67, 79, 167, 953, 1493, 3389, 4871, ...  
12  −11  47, 401, 509, 8609, ...  A213216 
^{*}Note: if b < 0 and n is even, then the numbers n are not included in the corresponding OEIS sequence.
A conjecture related to the generalized Mersenne primes:[3][101] (the conjecture predicts where is the next generalized Mersenne prime, if the conjecture is true, then there are infinitely many primes for all such (a,b) pairs)
For any integers a and b which satisfy the conditions:
 a > 1, −a < b < a.
 a and b are coprime. (thus, b cannot be 0)
 For every natural number r > 1, a and b are not both perfect rth powers. (since when a and b are both perfect rth powers, it can be shown that there are at most two n value such that a^{n} − b^{n}/a − b is prime, and these n values are r itself or a root of r, or 2)
 −4ab is not a perfect fourth power (if so, then the number has aurifeuillean factorization).
has prime numbers of the form
for prime p, the prime numbers will be distributed near the best fit line
where
and there are about
prime numbers of this form less than N.
 e is the base of the natural logarithm.
 γ is the Euler–Mascheroni constant.
 log_{a} is the logarithm in base a.
 R_{(a,b)}(n) is the nth prime number of the form a^{p} − b^{p}/a − b for prime p.
 C is a data fit constant which varies with a and b.
 δ is a data fit constant which varies with a and b.
 m is the largest natural number such that a and −b are both perfect 2^{m − 1}th powers.
We also have the following three properties:
 The number of prime numbers of the form a^{p} − b^{p}/a − b (with prime p) less than or equal to n is about e^{γ} log_{a}(log_{a}(n)).
 The expected number of prime numbers of the form a^{p} − b^{p}/a − b with prime p between n and an is about e^{γ}.
 The probability that number of the form a^{p} − b^{p}/a − b is prime (for prime p) is about e^{γ}/p log_{e}(a).
If this conjecture is true, then for all such (a,b) pairs, let q be the nth prime of the form a^{p} − b^{p}/a − b, the graph of log_{a}(log_{a}(q)) versus n is almost linear. (See [3])
When a = b + 1, it is (b + 1)^{n} − b^{n}, a difference of two consecutive perfect nth powers, and if a^{n} − b^{n} is prime, then a must be b + 1, because it is divisible by a − b.
Least n such that (b + 1)^{n} − b^{n} is prime are
 2, 2, 2, 3, 2, 2, 7, 2, 2, 3, 2, 17, 3, 2, 2, 5, 3, 2, 5, 2, 2, 229, 2, 3, 3, 2, 3, 3, 2, 2, 5, 3, 2, 3, 2, 2, 3, 3, 2, 7, 2, 3, 37, 2, 3, 5, 58543, 2, 3, 2, 2, 3, 2, 2, 3, 2, 5, 3, 4663, 54517, 17, 3, 2, 5, 2, 3, 3, 2, 2, 47, 61, 19, ... (sequence A058013 in the OEIS)
Least b such that (b + 1)^{prime(n)} − b^{prime(n)} is prime are
See also
 Repunit
 Fermat prime
 Power of two
 Erdős–Borwein constant
 Mersenne conjectures
 Mersenne twister
 Double Mersenne number
 Prime95 / MPrime
 Great Internet Mersenne Prime Search (GIMPS)
 Largest known prime number
 Titanic prime
 Gigantic prime
 Megaprime
 Wieferich prime
 Wagstaff prime
 Cullen prime
 Woodall prime
 Proth prime
 Solinas prime
 Gillies' conjecture
 Williams number
References
 Regius, Hudalricus (1536). Utrisque Arithmetices Epitome.
 "GIMPS Project Discovers Largest Known Prime Number: 2^{82,589,933}1". Mersenne Research, Inc. 21 December 2018. Retrieved 21 December 2018.
 Caldwell, Chris. "Heuristics: Deriving the Wagstaff Mersenne Conjecture".
 Chris K. Caldwell, Mersenne Primes: History, Theorems and Lists
 The Prime Pages, Mersenne's conjecture.
 Cole, F. N. (1903), "On the factoring of large numbers", Bull. Amer. Math. Soc., 10 (3): 134–137, doi:10.1090/S000299041903010799, JFM 34.0216.04
 Bell, E.T. and Mathematical Association of America (1951). Mathematics, queen and servant of science. McGrawHill New York. p. 228.
 "h2g2: Mersenne Numbers". BBC News. Archived from the original on December 5, 2014.
 Horace S. Uhler (1952). "A Brief History of the Investigations on Mersenne Numbers and the Latest Immense Primes". Scripta Mathematica. 18: 122–131.
 Brian Napper, The Mathematics Department and the Mark 1.
 The Prime Pages, The Prime Glossary: megaprime.
 Maugh II, Thomas H. (20080927). "UCLA mathematicians discover a 13milliondigit prime number". Los Angeles Times. Retrieved 20110521.
 Tia Ghose. "Largest Prime Number Discovered". Scientific American. Retrieved 20130207.
 Cooper, Curtis (7 January 2016). "Mersenne Prime Number discovery – 2^{74207281} − 1 is Prime!". Mersenne Research, Inc. Retrieved 22 January 2016.
 Brook, Robert (January 19, 2016). "Prime number with 22 million digits is the biggest ever found". New Scientist. Retrieved 19 January 2016.
 Chang, Kenneth (21 January 2016). "New Biggest Prime Number = 2 to the 74 Mil ... Uh, It's Big". The New York Times. Retrieved 22 January 2016.
 "Milestones".
 "Mersenne Prime Discovery  2^772329171 is Prime!". www.mersenne.org. Retrieved 20180103.
 "GIMPS Discovers Largest Known Prime Number: 2^82,589,9331". Retrieved 20190101.
 Will Edgington's Mersenne Page Archived 20141014 at the Wayback Machine
 Caldwell, Chris K. "Proof of a result of Euler and Lagrange on Mersenne Divisors". Prime Pages.
 There is no mentioning among the ancient Egyptians of prime numbers, and they did not have any concept for prime numbers known today. In the Rhind papyrus (1650 BC) the Egyptian fraction expansions have fairly different forms for primes and composites, so it may be argued that they knew about prime numbers. "The Egyptians used ($) in the table above for the first primes r = 3, 5, 7, or 11 (also for r = 23). Here is another intriguing observation: That the Egyptians stopped the use of ($) at 11 suggests they understood (at least some parts of) Eratosthenes's Sieve 2000 years before Eratosthenes 'discovered' it." The Rhind 2/n Table [Retrieved 20121111]. In the school of Pythagoras (b. about 570 – d. about 495 BC) and the Pythagoreans, we find the first sure observations of prime numbers. Hence the first two Mersenne primes, 3 and 7, were known to and may even be said to have been discovered by them. There is no reference, though, to their special form 2^{2} − 1 and 2^{3} − 1 as such. The sources to the knowledge of prime numbers among the Pythagoreans are late. The Neoplatonic philosopher Iamblichus, AD c. 245–c. 325, states that the Greek Platonic philosopher Speusippus, c. 408 – 339/8 BC, wrote a book named On Pythagorean Numbers. According to Iamblichus this book was based on the works of the Pythagorean Philolaus, c. 470–c. 385 BC, who lived a century after Pythagoras, 570 – c. 495 BC. In his Theology of Arithmetic in the chapter On the Decad, Iamblichus writes: "Speusippus, the son of Plato's sister Potone, and head of the Academy before Xenocrates, compiled a polished little book from the Pythagorean writings which were particularly valued at any time, and especially from the writings of Philolaus; he entitled the book On Pythagorean Numbers. In the first half of the book, he elegantly expounds linear numbers [that is, prime numbers], polygonal numbers and all sorts of plane numbers, solid numbers and the five figures which are assigned to the elements of the universe, discussing both their individual attributes and their shared features, and their proportionality and reciprocity." Iamblichus The Theology of Arithmetic translated by Robin Waterfiled, 1988, p. 112f. [Retrieved 20121111]. Iamblichus also gives us a direct quote from Speusippus' book where Speusippus among other things writes: "Secondly, it is necessary for a perfect number [the concept "perfect number" is not used here in a modern sense] to contain an equal amount of prime and incomposite numbers, and secondary and composite numbers." Iamblichus The Theology of Arithmetic translated by Robin Waterfiled, 1988, p. 113. [Retrieved 20121111]. For the Greek original text, see Speusippus of Athens: A Critical Study with a Collection of the Related Texts and Commentary by Leonardo Tarán, 1981, p. 140 line 21–22 [Retrieved 20121111] In his comments to Nicomachus of Gerasas's Introduction to Arithmetic, Iamblichus also mentions that Thymaridas, ca. 400 BC – ca. 350 BC, uses the term rectilinear for prime numbers, and that Theon of Smyrna, fl. AD 100, uses euthymetric and linear as alternative terms. Nicomachus of Gerasa, Introduction to Arithmetic, 1926, p. 127 [Retrieved 20121111] It is unclear though when this said Thymaridas lived. "In a highly suspect passage in Iamblichus, Thymaridas is listed as a pupil of Pythagoras himself." Pythagoreanism [Retrieved 20121111] Before Philolaus, c. 470–c. 385 BC, we have no proof of any knowledge of prime numbers.
 "Euclid's Elements, Book IX, Proposition 36".
 The Prime Pages, Mersenne Primes: History, Theorems and Lists.
 We find the oldest (undisputed) note of the result in Codex nr. 14908, which origins from Bibliotheca monasterii ord. S. Benedicti ad S. Emmeramum Ratisbonensis now in the archive of the Bayerische Staatsbibliothek, see "Halm, Karl / Laubmann, Georg von / Meyer, Wilhelm: Catalogus codicum latinorum Bibliothecae Regiae Monacensis, Bd.: 2,2, Monachii, 1876, p. 250". [retrieved on 20120917] The Codex nr. 14908 consists of 10 different medieval works on mathematics and related subjects. The authors of most of these writings are known. Some authors consider the monk Fridericus Gerhart (Amman), 1400–1465 (Frater Fridericus Gerhart monachus ordinis sancti Benedicti astrologus professus in monasterio sancti Emmerani diocesis Ratisponensis et in ciuitate eiusdem) to be the author of the part where the prime number 8191 is mentioned. Geschichte Der Mathematik [retrieved on 20120917] The second manuscript of Codex nr. 14908 has the name "Regulae et exempla arithmetica, algebraica, geometrica" and the 5th perfect number and all is factors, including 8191, are mentioned on folio no. 34 a tergo (backside of p. 34). Parts of the manuscript have been published in Archiv der Mathematik und Physik, 13 (1895), pp. 388–406 [retrieved on 20120923]
 "A i lettori. Nel trattato de' numeri perfetti, che giàfino dell anno 1588 composi, oltrache se era passato auáti à trouarne molti auertite molte cose, se era anco amplamente dilatatala Tauola de' numeri composti , di ciascuno de' quali si vedeano per ordine li componenti, onde preposto unnum." p. 1 in Trattato de' nvumeri perfetti Di Pietro Antonio Cataldo 1603. http://fermi.imss.fi.it/rd/bdv?/bdviewer@selid=1373775#
 pp. 13–18 in Trattato de' nvumeri perfetti Di Pietro Antonio Cataldo 1603. http://fermi.imss.fi.it/rd/bdv?/bdviewer@selid=1373775#
 pp. 18–22 in Trattato de' nvumeri perfetti Di Pietro Antonio Cataldo 1603. http://fermi.imss.fi.it/rd/bdv?/bdviewer@selid=1373775#
 http://bibliothek.bbaw.de/bbaw/bibliothekdigital/digitalequellen/schriften/anzeige/index_html?band=03nouv/1772&seite:int=36 Nouveaux Mémoires de l'Académie Royale des Sciences et BellesLettres 1772, pp. 35–36 EULER, Leonhard: Extrait d'une lettre à M. Bernoulli, concernant le Mémoire imprimé parmi ceux de 1771. p. 318 [intitulé: Recherches sur les diviseurs de quelques nombres très grands compris dans la somme de la progression géométrique 1 + 101 + 102 + 103 + ... + 10T = S]. Retrieved 20111002.
 http://primes.utm.edu/notes/by_year.html#31 The date and year of discovery is unsure. Dates between 1752 and 1772 are possible.
 Chris K. Caldwell. "Modular restrictions on Mersenne divisors". Primes.utm.edu. Retrieved 20110521.
 “En novembre de l’année 1883, dans la correspondance de notre Académie se trouve une communication qui contient l’assertion que le nombre 2^{61} − 1 = 2305843009213693951 est un nombre premier. /…/ Le tome XLVIII des Mémoires Russes de l’Académie /…/ contient le compterendu de la séance du 20 décembre 1883, dans lequel l’objet de la communication du père Pervouchine est indiqué avec précision.” Bulletin de l'Académie Impériale des Sciences de St.Pétersbourg, s. 3, v. 31, 1887, cols. 532–533. https://www.biodiversitylibrary.org/item/107789#page/277/mode/1up [retrieved 20120917] See also Mélanges mathématiques et astronomiques tirés du Bulletin de l’Académie impériale des sciences de St.Pétersbourg v. 6 (1881–1888), pp. 553–554. See also Mémoires de l'Académie impériale des sciences de St.Pétersbourg: Sciences mathématiques, physiques et naturelles, vol. 48
 Powers, R. E. (1 January 1911). "The Tenth Perfect Number". The American Mathematical Monthly. 18 (11): 195–197. doi:10.2307/2972574. JSTOR 2972574.
 "M. E. Fauquenbergue a trouvé ses résultats depuis Février, et j’en ai reçu communication le 7 Juin; M. Powers a envoyé le 1^{er} Juin un cablógramme à M. Bromwich [secretary of London Mathematical Society] pour M_{107}. Sur ma demande, ces deux auteurs m’ont adressé leurs remarquables résultats, et je m’empresse de les publier dans nos colonnes, avec nos felicitations." p. 103, André Gérardin, Nombres de Mersenne pp. 85, 103–108 in SphinxŒdipe. [Journal mensuel de la curiosité, de concours & de mathématiques.] v. 9, No. 1, 1914.
 "Power's cable announcing this same result was sent to the London Math. So. on 1 June 1914." Mersenne's Numbers, Scripta Mathematica, v. 3, 1935, pp. 112–119 http://primes.utm.edu/mersenne/LukeMirror/lit/lit_008s.htm [retrieved 20121013]
 http://plms.oxfordjournals.org/content/s213/1/1.1.full.pdf Proceedings / London Mathematical Society (1914) s2–13 (1): 1. Result presented at a meeting with London Mathematical Society on June 11, 1914. Retrieved 20111002.
 The Prime Pages, M_{107}: Fauquembergue or Powers?.
 http://visualiseur.bnf.fr/CadresFenetre?O=NUMM3039&I=166&M=chemindefer Presented at a meeting with Académie des sciences (France) on January 10, 1876. Retrieved 20111002.
 "Using the standard Lucas test for Mersenne primes as programmed by R. M. Robinson, the SWAC has discovered the primes 2^{521} − 1 and 2^{607} − 1 on January 30, 1952." D. H. Lehmer, Recent Discoveries of Large Primes, Mathematics of Computation, vol. 6, No. 37 (1952), p. 61, http://www.ams.org/journals/mcom/195206037/S0025571852994040/S0025571852994040.pdf [Retrieved 20120918]
 "The program described in Note 131 (c) has produced the 15th Mersenne prime 2^{1279} − 1 on June 25. The SWAC tests this number in 13 minutes and 25 seconds." D. H. Lehmer, A New Mersenne Prime, Mathematics of Computation, vol. 6, No. 39 (1952), p. 205, http://www.ams.org/journals/mcom/195206039/S0025571852993873/S0025571852993873.pdf [Retrieved 20120918]
 "Two more Mersenne primes, 2^{2203} − 1 and 2^{2281} − 1, were discovered by the SWAC on October 7 and 9, 1952." D. H. Lehmer, Two New Mersenne Primes, Mathematics of Computation, vol. 7, No. 41 (1952), p. 72, http://www.ams.org/journals/mcom/195307041/S0025571853993715/S0025571853993715.pdf [Retrieved 20120918]
 "On September 8, 1957, the Swedish electronic computer BESK established that the Mersenne number M_{3217} = 2^{3217} − 1 is a prime." Hans Riesel, A New Mersenne Prime, Mathematics of Computation, vol. 12 (1958), p. 60, http://www.ams.org/journals/mcom/195812061/S00255718195800997526/S00255718195800997526.pdf [Retrieved 20120918]
 A. Hurwitz and J. L. Selfridge, Fermat numbers and perfect numbers, Notices of the American Mathematical Society, v. 8, 1961, p. 601, abstract 587104.
 "If p is prime, M_{p} = 2^{p} − 1 is called a Mersenne number. The primes M_{4253} and M_{4423} were discovered by coding the LucasLehmer test for the IBM 7090." Alexander Hurwitz, New Mersenne Primes, Mathematics of Computation, vol. 16, No. 78 (1962), pp. 249–251, http://www.ams.org/journals/mcom/196216078/S0025571819620146162X/S0025571819620146162X.pdf [Retrieved 20120918]
 "The primes M_{9689}, M_{9941}, and M_{11213} which are now the largest known primes, were discovered by Illiac II at the Digital Computer Laboratory of the University of Illinois." Donald B. Gillies, Three New Mersenne Primes and a Statistical Theory, Mathematics of Computation, vol. 18, No. 85 (1964), pp. 93–97, http://www.ams.org/journals/mcom/196418085/S00255718196401597746/S00255718196401597746.pdf [Retrieved 20120918]
 "On the evening of March 4, 1971, a zero LucasLehmer residue for p = p_{24} = 19937 was found. Hence, M_{19937} is the 24th Mersenne prime." Bryant Tuckerman, The 24th Mersenne Prime, Proceedings of the National Academy of Sciences of the United States of America, vol. 68:10 (1971), pp. 2319–2320, http://www.pnas.org/content/68/10/2319.full.pdf [Retrieved 20120918]
 "On October 30, 1978 at 9:40 pm, we found M_{21701} to be prime. The CPU time required for this test was 7:40:20. Tuckerman and Lehmer later provided confirmation of this result." Curt Noll and Laura Nickel, The 25th and 26th Mersenne Primes, Mathematics of Computation, vol. 35, No. 152 (1980), pp. 1387–1390, http://www.ams.org/journals/mcom/198035152/S00255718198005835174/S00255718198005835174.pdf [Retrieved 20120918]
 "Of the 125 remaining M_{p} only M_{23209} was found to be prime. The test was completed on February 9, 1979 at 4:06 after 8:39:37 of CPU time. Lehmer and McGrogan later confirmed the result." Curt Noll and Laura Nickel, The 25th and 26th Mersenne Primes, Mathematics of Computation, vol. 35, No. 152 (1980), pp. 1387–1390, http://www.ams.org/journals/mcom/198035152/S00255718198005835174/S00255718198005835174.pdf [Retrieved 20120918]
 David Slowinski, "Searching for the 27th Mersenne Prime", Journal of Recreational Mathematics, v. 11(4), 1978–79, pp. 258–261, MR 80g #10013
 "The 27th Mersenne prime. It has 13395 digits and equals 2^{44497} – 1. [...] Its primeness was determined on April 8, 1979 using the Lucas–Lehmer test. The test was programmed on a CRAY1 computer by David Slowinski & Harry Nelson." (p. 15) "The result was that after applying the Lucas–Lehmer test to about a thousand numbers, the code determined, on Sunday, April 8th, that 2^{44497} − 1 is, in fact, the 27th Mersenne prime." (p. 17), David Slowinski, "Searching for the 27th Mersenne Prime", Cray Channels, vol. 4, no. 1, (1982), pp. 15–17.
 "An FFT containing 8192 complex elements, which was the minimum size required to test M_{110503}, ran approximately 11 minutes on the SX2. The discovery of M_{110503} (January 29, 1988) has been confirmed." W. N. Colquitt and L. Welsh, Jr., A New Mersenne Prime, Mathematics of Computation, vol. 56, No. 194 (April 1991), pp. 867–870, http://www.ams.org/journals/mcom/199156194/S00255718199110688239/S00255718199110688239.pdf [Retrieved 20120918]
 "This week, two computer experts found the 31st Mersenne prime. But to their surprise, the newly discovered prime number falls between two previously known Mersenne primes. It occurs when p = 110,503, making it the thirdlargest Mersenne prime known." I. Peterson, Priming for a lucky strike Science News; 2/6/88, Vol. 133 Issue 6, pp. 85–85. http://ehis.ebscohost.com/ehost/detail?vid=3&hid=23&sid=9a9d7493ffed410b9b59b86c63a93bc4%40sessionmgr10&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=afh&AN=8824187 [Retrieved 20120918]
 "Mersenne Prime Numbers". Omes.unibielefeld.de. 20110105. Retrieved 20110521.
 "Slowinski, a software engineer for Cray Research Inc. in Chippewa Falls, discovered the number at 11:36 a.m. Monday. [that is, 1983 September 19]" Jim Higgins, "Elusive numeral's number is up" and "Scientist finds big number" in The Milwaukee Sentinel – Sep 24, 1983, p. 1, p. 11 [retrieved 20121023]
 "The number is the 30th known example of a Mersenne prime, a number divisible only by 1 and itself and written in the form 2^{p} − 1, where the exponent p is also a prime number. For instance, 127 is a Mersenne number for which the exponent is 7. The record prime number's exponent is 216,091." I. Peterson, Prime time for supercomputers Science News; 9/28/85, Vol. 128 Issue 13, p. 199. http://ehis.ebscohost.com/ehost/detail?vid=4&hid=22&sid=c11090a24670469f8f75947b593a56a0%40sessionmgr10&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=afh&AN=8840537 [Retrieved 20120918]
 "Slowinski's program also found the 28th in 1982, the 29th in 1983, and the 30th [known at that time] this past Labor Day weekend. [that is, August 31September 1, 1985]" Rad Sallee, "`Supercomputer'/Chevron calculating device finds a bigger prime number" Houston Chronicle, Friday 09/20/1985, Section 1, Page 26, 4 Star Edition [retrieved 20121023]
 The Prime Pages, The finding of the 32nd Mersenne.
 Chris Caldwell, The Largest Known Primes.
 Crays press release
 "Slowinskis email".
 Silicon Graphics' press release https://web.archive.org/web/19970606011821/http://www.sgi.com/Headlines/1996/September/prime.html [Retrieved 20120920]
 The Prime Pages, A Prime of Record Size! 2^{1257787} – 1.
 GIMPS Discovers 35th Mersenne Prime.
 GIMPS Discovers 36th Known Mersenne Prime.
 GIMPS Discovers 37th Known Mersenne Prime.
 GIMPS Finds First MillionDigit Prime, Stakes Claim to $50,000 EFF Award.
 GIMPS, Researchers Discover Largest MultiMillionDigit Prime Using Entropia Distributed Computing Grid.
 GIMPS, Mersenne Project Discovers Largest Known Prime Number on WorldWide Volunteer Computer Grid.
 GIMPS, Mersenne.org Project Discovers New Largest Known Prime Number, 2^{24,036,583} – 1.
 GIMPS, Mersenne.org Project Discovers New Largest Known Prime Number, 2^{25,964,951} – 1.
 GIMPS, Mersenne.org Project Discovers New Largest Known Prime Number, 2^{30,402,457} – 1.
 GIMPS, Mersenne.org Project Discovers Largest Known Prime Number, 2^{32,582,657} – 1.
 Titanic Primes Raced to Win $100,000 Research Award. Retrieved on 20080916.
 "On April 12th [2009], the 47th known Mersenne prime, 2^{42,643,801} – 1, a 12,837,064 digit number was found by Odd Magnar Strindmo from Melhus, Norway! This prime is the second largest known prime number, a "mere" 141,125 digits smaller than the Mersenne prime found last August.", The List of Largest Known Primes Home Page, http://primes.utm.edu/primes/page.php?id=88847 [retrieved 20120918]
 "GIMPS Discovers 48th Mersenne Prime, 2^{57,885,161} − 1 is now the Largest Known Prime". Great Internet Mersenne Prime Search. Retrieved 20160119.
 "List of known Mersenne prime numbers". Retrieved 29 November 2014.
 "GIMPS Project Discovers Largest Known Prime Number: 2^{77,232,917}1". Mersenne Research, Inc. 3 January 2018. Retrieved 3 January 2018.
 "List of known Mersenne prime numbers". Retrieved 3 January 2018.
 GIMPS Milestones Report. Retrieved 20190517
 Caldwell, "The Largest Known Prime by Year: A Brief History" from the Prime Pages website, University of Tennessee at Martin.
 Thorsten Kleinjung, Joppe Bos, Arjen Lenstra "Mersenne Factorization Factory" http://eprint.iacr.org/2014/653.pdf
 Henri Lifchitz and Renaud Lifchitz. "PRP Top Records". Retrieved 20180321.
 "Exponent Status for M1277". Retrieved 20180622.
 Petković, Miodrag (2009). Famous Puzzles of Great Mathematicians. AMS Bookstore. p. 197. ISBN 9780821848142.
 Alan Chamberlin. "JPL SmallBody Database Browser". Ssd.jpl.nasa.gov. Retrieved 20110521.
 "OEIS A016131". The OnLine Encyclopedia of Integer Sequences.
 Tayfun Pay, and James L. Cox. "An overview of some semantic and syntactic complexity classes".
 "A research of Mersenne and Fermat primes". Archived from the original on 20120529.
 Solinas, Jerome A. (1 January 2011). "Generalized Mersenne Prime". In Tilborg, Henk C. A. van; Jajodia, Sushil (eds.). Encyclopedia of Cryptography and Security. Springer US. pp. 509–510. doi:10.1007/9781441959065_32. ISBN 9781441959058.
 Chris Caldwell: The Prime Glossary: Gaussian Mersenne (part of the Prime Pages)
 Zalnezhad, Ali; Zalnezhad, Hossein; Shabani, Ghasem; Zalnezhad, Mehdi (March 2015). "Relationships and Algorithm in order to Achieve the Largest Primes". arXiv:1503.07688. Cite journal requires
journal=
(help)  (x, 1) and (x, −1) for x = 2 to 50
 (x, 1) for x = 2 to 160
 (x, −1) for x = 2 to 160
 (x + 1, x) for x = 1 to 160
 (x + 1, −x) for x = 1 to 40
 (x + 2, x) for odd x = 1 to 107
 (x, −1) for x = 2 to 200
 PRP records, search for (a^nb^n)/c, that is, (a, b)
 PRP records, search for (a^n+b^n)/c, that is, (a, −b)
 "Generalized Repunit Conjecture".
External links
Look up Mersenne prime in Wiktionary, the free dictionary. 
Wikinews has related news: 
 Hazewinkel, Michiel, ed. (2001) [1994], "Mersenne number", Encyclopedia of Mathematics, Springer Science+Business Media B.V. / Kluwer Academic Publishers, ISBN 9781556080104
 GIMPS home page
 GIMPS status — status page gives various statistics on search progress, typically updated every week, including progress towards proving the ordering of the largest known Mersenne primes
 GIMPS, known factors of Mersenne numbers
 M_{q} = (8x)^{2} − (3qy)^{2} Property of Mersenne numbers with prime exponent that are composite (PDF)
 M_{q} = x^{2} + d·y^{2} math thesis (PS)
 Grime, James. "31 and Mersenne Primes". Numberphile. Brady Haran.
 Mersenne prime bibliography with hyperlinks to original publications
 report about Mersenne primes — detection in detail (in German)
 GIMPS wiki
 Will Edgington's Mersenne Page — contains factors for small Mersenne numbers
 Known factors of Mersenne numbers
 Decimal digits and English names of Mersenne primes
 Prime curios: 2305843009213693951
 Factorization of Mersenne numbers M_{n}, with n odd, n up to 1199
 Factorization of Mersenne numbers M_{2n}, 2n up to 2398 (n up to 1199) or 2n is in the form 8k + 4 up to 4796 (n is on the form 4k + 2 up to 2398)
 OEIS sequence A250197 (Numbers n such that the left Aurifeuillian primitive part of 2^n+1 is prime)—Factorization of Mersenne numbers M_{n} (n up to 1280)
 Factorization of completely factored Mersenne numbers
 The Cunningham project, factorization of b^{n} ± 1, b = 2, 3, 5, 6, 7, 10, 11, 12
 Factorization of b^{n} ± 1, 2 ≤ b ≤ 12
 Factorization of a^{n} ± b^{n}, with coprime a, b, 2 ≤ b < a ≤ 12