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 A306181 #10 May 15 2025 17:09:30 %S A306181 1,5,28,235,1970,17201,149420,1295637,11178026,96047288,822418731, %T A306181 7020762655 %N A306181 Number of unrooted self-avoiding walks with n steps that can make turns from the set +-Pi/11, +-3*Pi/11, +-5*Pi/11, +-7*Pi/11, +-9*Pi/11. %C A306181 The turning angles are those of the regular 11-gon, with one vertex corresponding to the forbidden U-turn. The path may neither intersect nor touch itself anywhere. %H A306181 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 A306181 Hugo Pfoertner, <a href="http://www.randomwalk.de/sequences/a306181.htm">Illustration of walks of lengths <= 3</a>. %Y A306181 Cf. A266925, A037245, A306175, A151541, A306177, A306178, A306179, A306180, A306182. %K A306181 nonn,walk,more %O A306181 1,2 %A A306181 _Hugo Pfoertner_, Jun 23 2018 %E A306181 a(7)-a(12) from _Bert Dobbelaere_, May 15 2025