This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A241267 #11 Sep 08 2022 08:46:07 %S A241267 18,19,21,24,28,33,39,46,54,60,61,62,63,65,67,72,73,75,81,82,84,85,86, %T A241267 93,95,96,100,101,103,104,105,109,110,111,112,117,121,122,123,125,130, %U A241267 137,138,139,141,142,143,144,147,152,153,154,159,160,161,165,166 %N A241267 Numbers n such that 4*n^2 + 4*n + 653 is not prime. %H A241267 Vincenzo Librandi, <a href="/A241267/b241267.txt">Table of n, a(n) for n = 1..1000</a> %e A241267 19 is in this sequence because 4*19^2 + 4*19 + 653 = 2173 = 41*53. %t A241267 Select[Range[0, 250], ! PrimeQ[4 #^2 + 4 # + 653] &] %o A241267 (Magma) [n: n in [0..250] | not IsPrime(4*n^2+4*n+653)]; %Y A241267 Complement of A188459. %K A241267 nonn,easy %O A241267 1,1 %A A241267 _Vincenzo Librandi_, Apr 20 2014