%I #14 Sep 08 2022 08:46:05
%S 0,1,2,3,5,7,8,9,11,12,13,15,17,19,21,22,23,24,25,26,27,29,31,32,33,
%T 35,36,37,38,39,40,41,42,43,44,45,46,47,49,50,51,52,53,55,56,57,59,61,
%U 62,63,64,65,67,68,69,70,71,72,73,75,77,78,79,81,82,83,85,86,87,89,90
%N Numbers n such that 27*n + 1 is not prime.
%C Complement of A224467.
%H Vincenzo Librandi, <a href="/A228373/b228373.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Range[0, 120], ! PrimeQ[27 # + 1]&]
%o (Magma) [n: n in [0..120] | not IsPrime(27*n + 1)];
%Y Cf. A224467.
%K nonn,less,easy
%O 1,3
%A _Vincenzo Librandi_, Aug 21 2013