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 A058130 #7 Mar 30 2012 17:37:11 %S A058130 1,2,4,19,128,1344,20997,1479686 %N A058130 Number of asymmetric monoids (semigroups with identity) of order n. %H A058130 <a href="/index/Mo#monoids">Index entries for sequences related to monoids</a> %Y A058130 a(n)=A058136(n)*2-A058135(n). %K A058130 nonn,hard %O A058130 1,2 %A A058130 _Christian G. Bower_, Nov 13 2000 %E A058130 a(8) from _Christian G. Bower_, Dec 26 2006