A230809 Primes p of the form 60*n + 59 such that 2*p + 1 is also prime.

179, 239, 359, 419, 659, 719, 1019, 1439, 1499, 1559, 2039, 2339, 2399, 2459, 2699, 2819, 2939, 3299, 3359, 3539, 3779, 4019, 4919, 5039, 5279, 5399, 5639, 6899, 7079, 9059, 9419, 9479, 9539, 10799, 11519, 11579, 11699, 11939, 12119, 12899, 12959, 13619

Offset

1,1

Comments

Primes p such that 2*p + 1 divides Lucas(p) and Mersenne(p).

Links

Table of n, a(n) for n=1..42.

Eric Weisstein's World of Mathematics, Lucas Number

Eric Weisstein's World of Mathematics, Mersenne Number

Formula

A005384 INTERSECT A142799.

A002515 INTERSECT A215850.

Example

179 is in the sequence since it is prime and 359 is a factor of both Lucas(179) and Mersenne(179) = 2^179 - 1.

Prog

(Magma) [p : p in [59..13619 by 60] | IsPrime(p) and IsPrime(2*p+1)];
(PARI) forstep(p=59, 13619, 60, if(isprime(p)&&isprime(2*p+1), print1(p, ", ")));

Crossrefs

Subsequence of A142799, of A215850, and of A239548. Cf. A000032, A001348, A002515.

Sequence in context: A226928 A162164 A238893 * A335067 A142028 A146359

Adjacent sequences: A230806 A230807 A230808 * A230810 A230811 A230812

Keyword

nonn

Author

Arkadiusz Wesolowski, Oct 30 2013

Status

approved