A023230 Numbers k such that k and 8*k + 5 are both prime.

3, 7, 13, 19, 43, 67, 103, 109, 127, 139, 151, 181, 193, 199, 211, 223, 241, 277, 283, 349, 379, 397, 421, 433, 439, 463, 577, 601, 607, 613, 619, 727, 733, 787, 829, 853, 883, 967, 991, 1033, 1039, 1117, 1201, 1237, 1291, 1303, 1399, 1429, 1459, 1531, 1567, 1579

Offset

1,1

Links

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

Mathematica

lst={}; Do[p=Prime[n]; If[PrimeQ[8*p+5], AppendTo[lst, p]], {n, 6!}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 16 2009 *)
Select[Prime [Range[0, 300]], PrimeQ[8# + 5] &] (* Vincenzo Librandi, Sep 25 2012 *)

Prog

(Magma) [ p: p in PrimesUpTo(1580) | IsPrime(8*p+5) ]; // Klaus Brockhaus, Dec 21 2008
(PARI) select(p->isprime(8*p+5), primes(1000)) \\ Charles R Greathouse IV, Sep 25 2012

Crossrefs

Cf. A007521 (primes of form 8n+5), A105133 (numbers n such that 8n+5 is prime).

Sequence in context: A252091 A217035 A134765 * A194581 A106080 A393107

Adjacent sequences: A023227 A023228 A023229 * A023231 A023232 A023233

Keyword

nonn,easy

Author

David W. Wilson

Status

approved