OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Range[221], PrimeQ[6 # - 5] && ! PrimeQ[6 # - 1] &] (* T. D. Noe, Nov 09 2011 *)
PROG
(Magma) [ p div 6 +1: p in PrimesUpTo(1326) | not IsPrime(p+4) and p mod 6 eq 1 ]; // Bruno Berselli, Nov 09 2011
(PARI) is(n)=isprime(6*n-5) && !isprime(6*n-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Eleonora Echeverri-Toro, Nov 09 2011
STATUS
approved