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 A166569 #10 Sep 08 2022 08:45:48 %S A166569 4,7,9,14,15,19,20,21,24,26,28,29,32,33,34,35,37,39,42,44,46,48,49,54, %T A166569 55,56,58,59,63,64,66,69,70,72,74,77,78,79,81,83,84,85,89,91,92,94,95, %U A166569 96,98,99,100,101,103,104,105,109,111,112,113,114,115,117,119,124,125 %N A166569 Numbers n such that 12*n+7 is not prime. %H A166569 Vincenzo Librandi, <a href="/A166569/b166569.txt">Table of n, a(n) for n = 1..1000</a> %e A166569 Distribution of the terms in the following triangular array: %e A166569 *; %e A166569 *,*; %e A166569 *,*,*; %e A166569 *,*,*,*; %e A166569 *,4,*,*,*; %e A166569 *,*,7,*,*,*; %e A166569 *,*,*,*,*,*,*; %e A166569 *,*,*,*,15,*,*,*; %e A166569 *,*,*,*,*,20,*,*,*; %e A166569 *,*,*,*,*,*,*,*,*,*; %e A166569 *,9,*,*,*,*,*,32,*,*,*; %e A166569 *,*,14,*,*,*,*,*,39,*,*,*; etc. %e A166569 where * marks the non-integer values of (2*h*k + k + h - 3)/6 with h >= k >= 1. - _Vincenzo Librandi_, Jan 14 2013 %t A166569 Select[Range[0, 200], !PrimeQ[12 # + 7] &] (* _Vincenzo Librandi_, Jan 14 2013 *) %o A166569 (Magma) [n: n in [0..150] | not IsPrime(12*n+7)]; // _Vincenzo Librandi_, Jan 14 2013 %Y A166569 Cf. A167056. %K A166569 nonn,easy %O A166569 1,1 %A A166569 _Vincenzo Librandi_, Oct 29 2009