Named after | Marin Mersenne |
---|---|
Publication year | 1536 |
Author of publication | Regius, H. |
No. of known terms | 49 |
Conjectured no. of terms | Infinite |
Subsequence of | Mersenne numbers |
First terms | 3, 7, 31, 127 |
Largest known term | 274,207,281 − 1 (January 2016) |
OEIS index | A000668 |
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. |
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 that can be written in the form Mn = 2n − 1 for some integer n. They are named after Marin Mersenne, a French Minim friar, who studied them in the early 17th century. The first four Mersenne primes (sequence in the OEIS) are 3, 7, 31, and 127.
If n is a composite number then so is 2n − 1. (2ab − 1 is divisible by both 2a − 1 and 2b − 1.) The definition is therefore unchanged when written Mp = 2p − 1 where p is assumed prime.
More generally, numbers of the form Mn = 2n − 1 without the primality requirement are called Mersenne numbers. Mersenne numbers are sometimes defined to have the additional requirement that n be prime, equivalently that they be pernicious Mersenne numbers, namely those numbers whose binary representation contains a prime number of ones and no zeros. The smallest composite pernicious Mersenne number is 211 − 1 = 2047 = 23 × 89.
Mersenne primes Mp are also noteworthy due to their connection to perfect numbers.
As of January 2016[ref], 49 Mersenne primes are known. The largest known prime number 274,207,281 − 1 is a Mersenne prime.