A139314 Primes of the form 2^(2p - 1) - 1, where p is prime.

7, 31, 8191, 2305843009213693951

Offset

1,1

Comments

Primes in A139287.

This sequence is a subsequence of A000668. From A000043, a(5) = 2^3217 - 1.

The next term a(6) is an unknown Mersenne prime. [Washington Bomfim, Nov 18 2009]

a(5) has 969 digits. - Vincenzo Librandi, Dec 14 2010

The first three terms can be written as (n^3 - 1)/(n - 1) for some n. [Arkadiusz Wesolowski, May 09 2012]

Links

Michel Marcus, Table of n, a(n) for n = 1..5

Wikipedia, Mersenne prime

Prog

(Magma) [a: p in PrimesUpTo(4200) | IsPrime(a) where a is 2^(2*p-1)-1]; // Vincenzo Librandi, Dec 14 2010

Crossrefs

Cf. A139286, A139287.

Cf. A000668, A000043. [Washington Bomfim, Nov 18 2009]

Sequence in context: A253640 A191297 A134709 * A290969 A163083 A101329

Adjacent sequences: A139311 A139312 A139313 * A139315 A139316 A139317

Keyword

nonn

Author

Omar E. Pol, Apr 13 2008

Status

approved