A249384 Smallest odd prime number Q such that Q*2^P+1 is also prime, where P is a Mersenne prime exponent A000043(n).

3, 5, 3, 5, 5, 53, 11, 239, 53, 191, 1229, 5, 233, 347, 1367, 9767, 2063, 89, 14009, 3329, 19991, 50849, 2711, 337871, 46301, 2543, 413093, 1157111, 615161, 1138649, 3778427

Offset: 1

Author

Pierre CAMI, Oct 27 2014

Keywords

• nonn
• more

Crossrefs

Cf. A000043, A249382, A249383.

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