%I #9 Sep 08 2022 08:46:11

%S 1,4,5,8,10,12,14,15,16,19,21,22,23,27,29,30,32,35,36,38,40,42,43,44,

%T 46,48,49,50,52,53,56,57,58,59,60,61,63,64,66,67,71,75,77,78,79,80,81,

%U 82,83,85,87,88,92,93,95,99,103,104,105,106

%N Numbers k such that 90*k+1 is composite.

%D J. W. Helkenberg, Email message, Mar 02 2015.

%H Vincenzo Librandi, <a href="/A255491/b255491.txt">Table of n, a(n) for n = 1..7000</a>

%t Select[Range[200], !PrimeQ[90 # + 1] &] (* _Vincenzo Librandi_, Jun 09 2017 *)

%o (Magma) [n: n in [1..120]| not IsPrime(90*n+1)]; // _Vincenzo Librandi_, Jun 09 2017

%Y Complement of A181732.

%K nonn

%O 1,2

%A _N. J. A. Sloane_, Mar 03 2015