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 A083568 #4 May 11 2007 03:00:00 %S A083568 1,1,2,12,286,33592,23178480,108995910720,3973186258569120 %N A083568 Duplicate of A003121. %K A083568 dead %O A083568 1,3