A023231 Primes p such that 8*p + 7 is also prime.

2, 3, 5, 23, 29, 47, 53, 59, 89, 107, 113, 137, 179, 197, 227, 233, 257, 263, 293, 317, 359, 389, 419, 509, 557, 587, 593, 599, 617, 653, 659, 683, 839, 857, 863, 887, 947, 977, 1013, 1097, 1103, 1163, 1193, 1217, 1223, 1229, 1259, 1277, 1283, 1307, 1319, 1409

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Example

For p = 3, 8*p + 7 = 31;
for p = 179, 8*p + 7 = 1439.

Maple

a := proc (n) if isprime(n) = true and isprime(8*n+7) = true then n else end if end proc: seq(a(n), n = 1 .. 1500); # Emeric Deutsch, Dec 30 2008

Mathematica

Select[Prime@Range@500, PrimeQ[8 # + 7] &] (* Vincenzo Librandi, May 19 2014 *)

Prog

(Magma) [n: n in PrimesUpTo(1500) | IsPrime(8*n+7)]; // Vincenzo Librandi, Nov 20 2010

Crossrefs

Cf. A139487, A007522.

Sequence in context: A041195 A042141 A122004 * A034470 A237812 A138170

Adjacent sequences: A023228 A023229 A023230 * A023232 A023233 A023234

Keyword

nonn,easy

Author

David W. Wilson

Extensions

Edited by N. J. A. Sloane, Mar 11 2009 at the suggestion of R. J. Mathar

Status

approved