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 A143831 #4 Feb 20 2017 14:52:50
%S A143831 1,2,3,4,6,7,9,11,13,14,15,17,20,22,24,25,26,27,29,30,35,36,37,38,39,
%T A143831 46,48,55,59,61,68,69,72,75,77,79,82,88,91,93,94,102,105,107,108,115,
%U A143831 116,117,118,121,124,130,134,136,137,140,149,152,154,157,158,159,162,167
%N A143831 Numbers n such that 12n^2 - 1 is prime.
%t A143831 p = 12; a = {}; Do[k = p x^2 - 1; If[PrimeQ[k], AppendTo[a, x]], {x, 1, 1000}]; a
%o A143831 (PARI) is(n)=isprime(12*n^2-1) \\ _Charles R Greathouse IV_, Feb 20 2017
%Y A143831 Cf. A066436, A066049, A090686, A090684, A143826, A143827, A143828, A143829, A143830.
%K A143831 nonn
%O A143831 1,2
%A A143831 _Artur Jasinski_, Sep 02 2008