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 A316198 #6 Jul 04 2018 20:26:38 %S A316198 0,2,6,59,695,12198 %N A316198 Number of self-avoiding polygons with perimeter 2*n and sides = 1 that have vertex angles from the set 0, +-Pi/4, +-Pi/2, +-3*Pi/4, not counting rotations and reflections as distinct. %C A316198 Holes are excluded, i.e., the boundary path may nowhere touch or intersect itself. %H A316198 Contest Organizers, <a href="http://www.recmath.org/contest/Snakes/index.php">Al Zimmermann's Programming Contests - Snakes on a Plane</a>, Fall 2006. %H A316198 Hugo Pfoertner, <a href="http://www.randomwalk.de/sequences/a316198.htm">Illustration of polygons of perimeter <= 10</a>. %Y A316198 Cf. A306178, A316195, A316197. %K A316198 nonn,walk,more %O A316198 1,2 %A A316198 _Hugo Pfoertner_, Jul 04 2018