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 A230433 #9 Oct 19 2013 05:06:53
%S A230433 1,7,13,17,33,43,205,287,669,1161,1166,3753,6095,18123,28041
%N A230433 Numbers k such that 43^k + 4 is prime.
%C A230433 a(16) > 5*10^4.
%t A230433 Do[If[PrimeQ[43^k + 4], Print[k]], {k, 50000}]
%Y A230433 Cf. A058958.
%K A230433 nonn,more
%O A230433 1,2
%A A230433 _Robert Price_, Oct 18 2013