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 A140291 #16 Mar 17 2013 13:26:42 %S A140291 1,3,7,9,13,15,31,37,51,73,99,111,115,133,141,151 %N A140291 Erroneous version of A118561. %K A140291 dead %O A140291 1,2