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 A316192 #9 Jul 07 2018 19:29:27 %S A316192 0,0,1,3,4,22,69,418,2210,14024 %N A316192 Number of self-avoiding polygons with perimeter n and sides = 1 that have vertex angles from the set 0, +-Pi/6, +-*Pi/3, +-Pi/2, +-2*Pi/3, +-5*Pi/6, not counting rotations and reflections as distinct. %C A316192 Holes are excluded, i.e., the boundary path may nowhere touch or intersect itself. %H A316192 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 A316192 Hugo Pfoertner, <a href="http://www.randomwalk.de/sequences/a316192.htm">Illustration of polygons of perimeter <= 8</a>. %Y A316192 Cf. A258206, A266549, A284869, A306182, A316195, A316197, A316198, A316199, A316200, A316201. %K A316192 nonn,walk,more %O A316192 1,4 %A A316192 _Hugo Pfoertner_, Jul 07 2018