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
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, Sep 08 2012
STATUS
approved