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 A306179 #9 May 15 2025 15:52:01 %S A306179 1,4,19,128,861,6051,42475,297993,2081607,14485077,100475175, %T A306179 694838429,4793805002 %N A306179 Number of unrooted self-avoiding walks with n steps that can make turns from the set +-Pi/9, +-3*Pi/9, +-5*Pi/9, +-7*Pi/9. %C A306179 The turning angles are those of the regular nonagon, with one vertex corresponding to the forbidden U-turn. The path may neither intersect nor touch itself anywhere. %H A306179 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 A306179 Hugo Pfoertner, <a href="http://www.randomwalk.de/sequences/a306179.htm">Illustration of walks of lengths <= 3</a>. %Y A306179 Cf. A266925, A037245, A306175, A151541, A306177, A306178, A306180, A306181, A306182. %K A306179 nonn,walk,more %O A306179 1,2 %A A306179 _Hugo Pfoertner_, Jun 23 2018 %E A306179 a(7)-a(13) from _Bert Dobbelaere_, May 15 2025