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 A058153 #9 Jul 15 2021 18:57:59 %S A058153 1,4,33,624,20610,1252032,129552080,63141932606 %N A058153 Number of labeled monoids of order n. %H A058153 Eric Postpischil, <a href="http://groups.google.com/groups?&hl=en&lr=&ie=UTF-8&selm=11802%40shlump.nac.dec.com&rnum=2">Posting to sci.math newsgroup, May 21 1990</a> %H A058153 <a href="/index/Mo#monoids">Index entries for sequences related to monoids</a> %Y A058153 a(n) = A058154(n)*n. %K A058153 nonn,more %O A058153 1,2 %A A058153 _Christian G. Bower_, Nov 14 2000 %E A058153 a(8) from _Christian G. Bower_, Dec 28 2006