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%I #11 Sep 08 2022 08:46:07
%S 18,19,21,24,28,33,39,46,54,60,61,62,63,65,67,72,73,75,81,82,84,85,86,
%T 93,95,96,100,101,103,104,105,109,110,111,112,117,121,122,123,125,130,
%U 137,138,139,141,142,143,144,147,152,153,154,159,160,161,165,166
%N Numbers n such that 4*n^2 + 4*n + 653 is not prime.
%H Vincenzo Librandi, <a href="/A241267/b241267.txt">Table of n, a(n) for n = 1..1000</a>
%e 19 is in this sequence because 4*19^2 + 4*19 + 653 = 2173 = 41*53.
%t Select[Range[0, 250], ! PrimeQ[4 #^2 + 4 # + 653] &]
%o (Magma) [n: n in [0..250] | not IsPrime(4*n^2+4*n+653)];
%Y Complement of A188459.
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Apr 20 2014