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 A058138 #5 Mar 30 2012 17:37:11 %S A058138 1,3,9,32,219,5585 %N A058138 Monoids of order n with 2 idempotents. %H A058138 <a href="/index/Mo#monoids">Index entries for sequences related to monoids</a> %Y A058138 Column 2 of A058137. %K A058138 nonn,more %O A058138 2,2 %A A058138 _Christian G. Bower_, Nov 14 2000