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 A316196 #5 Jun 27 2018 18:43:39 %S A316196 0,0,1,1,1,4,3,10,9,36,27,129,90,449,331 %N A316196 Number of symmetric self-avoiding polygons on hexagonal lattice with perimeter n, not counting rotations and reflections as distinct. %H A316196 Hugo Pfoertner, <a href="http://www.randomwalk.de/sequences/a284869.htm">Illustration of polygons of perimeter <= 11</a>. %Y A316196 Cf. A036418, A284869, A306176. %K A316196 nonn,walk,more %O A316196 1,6 %A A316196 _Hugo Pfoertner_, Jun 27 2018