A107438 Primes p such that 7*p+2 or 2*p+7 is prime.

2, 3, 5, 11, 17, 23, 41, 47, 53, 71, 83, 101, 107, 113, 131, 137, 167, 173, 191, 197, 227, 251, 257, 281, 293, 311, 317, 347, 353, 383, 401, 431, 461, 467, 503, 521, 563, 587, 593, 641, 647, 677, 683, 701, 743, 773, 797, 821, 827, 857, 863, 887, 911, 941, 947

Offset: 1

Author

Zak Seidov, May 26 2005

Keywords

• nonn

Crossrefs

Cf. A105760 Numbers n such that (2*n + 7) is prime; A105772 Numbers n such that (7*n + 2) is prime.

Programs

Mathematica

Select[Prime[Range[220]], PrimeQ[2#+7]||PrimeQ[7#+2]&] (* Shepherd *)

PARI

isok(n) = isprime(n) && (isprime(7*n+2) || isprime(2*n+7)); \\ Michel Marcus, Oct 06 2013

Extensions

Edited by Rick L. Shepherd, Feb 01 2006