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 A058135 #6 Mar 30 2012 17:37:11 %S A058135 1,2,4,13,54,322,2545 %N A058135 Number of asymmetric self-converse monoids (semigroups with identity) of order n. %H A058135 <a href="/index/Mo#monoids">Index entries for sequences related to monoids</a> %Y A058135 a(n)=A058136(n)*2-A058130(n). %K A058135 nonn,more %O A058135 1,2 %A A058135 _Christian G. Bower_, Nov 13 2000