A216495 Primes p with property that there exists a number d>0 such that numbers p-d, p-2*d are primes.

7, 11, 17, 19, 23, 29, 31, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283

Offset

1,1

Comments

Conjecture: only 5 primes are not in the sequence: 2, 3, 5, 13, 37.

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..9617

Mathematica

prms = 2; fQ[p_] := Module[{d = 1}, While[prms*d < p && Union[PrimeQ[p - Range[prms]*d]] != {True}, d++]; prms*d < p]; Select[Prime[Range[2, PrimePi[283]]], fQ] (* T. D. Noe, Sep 08 2012 *)

Prog

(PARI) is(n)=my(t); forprime(p=2, n-4, if(isprime((t=(n-p)\2)+p) && isprime(2*t+p) && isprime(n), return(1))); 0 \\ Charles R Greathouse IV, Sep 10 2014

Crossrefs

Cf. A094383, A216497, A216498, A216468.

Sequence in context: A147956 A163996 A117743 * A034849 A269256 A106070

Adjacent sequences: A216492 A216493 A216494 * A216496 A216497 A216498

Keyword

nonn

Author

Alex Ratushnyak, Sep 08 2012

Status

approved