A249383 Smallest odd prime number Q such that Q*2^P-1 is also prime with P Mersenne prime exponent A000043(n).

3, 3, 7, 3, 31, 7, 61, 43, 79, 19, 739, 103, 2707, 4513, 139, 13, 4027, 28027, 14029, 87151, 11257, 8677, 122449, 104161, 113287, 216211, 150097, 862009, 876721, 414949, 4590451, 1391281

Offset: 1

Author

Pierre CAMI, Oct 27 2014

Keywords

• nonn

Comments

a(32) is a 227838-digit certified prime.

Does a(n) exist for each n? - Charles R Greathouse IV, Oct 28 2014

Crossrefs

Cf. A000043, A249382, A249384.

Programs

PARI

lista(nn) = {vmp = readvec("b000043.txt"); for (n=1, nn, k=2; while(!isprime(prime(k)*2^vmp[n]-1), k++); print1(prime(k), ", "););} \\ Michel Marcus, Oct 27 2014