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 A226680 #11 Jul 02 2013 13:23:25 %S A226680 1,23,139,311,3299,7153,185357 %N A226680 Integer k associated with the record-breaking number A226679(n) of primitive Collatz-like 3x-k cycles. %C A226680 a(8)>315187. %Y A226680 Cf. A226664. %K A226680 nonn,more %O A226680 1,2 %A A226680 _Geoffrey H. Morley_, Jun 15 2013