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 A252653 #21 Mar 03 2017 19:36:13 %S A252653 1,1,2,4,8,18,46,115,300,781,2097,5541 %N A252653 Number of free polyominoes with n cells containing a complete self-avoiding walk. %H A252653 Ernest French, <a href="http://fuseki.net/polycover/index.html">Covering Free Polyominos</a> %Y A252653 Cf. A000105, A213376, A283162. %K A252653 nonn,walk,more %O A252653 1,3 %A A252653 _Ernest French_, Mar 21 2015