1,1

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

Select[Range[2, 205], ! PrimeQ[6 # - 5] && PrimeQ[6 # - 1] &] (* T. N. Noe, Nov 09 2011 *)

(MAGMA) [ p div 6 +1: n in [4..204] | not IsPrime(p-4) and p mod 6 eq 5 where p is NthPrime(n) ]; // Bruno Berselli, Nov 09 2011

Cf. A186243.

Sequence in context: A235033 A327593 A282757 * A155470 A266399 A164709

Adjacent sequences: A199715 A199716 A199717 * A199719 A199720 A199721

nonn,easy

Eleonora Echeverri-Toro, Nov 09 2011

approved