

A316199


Number of selfavoiding polygons with perimeter 2*n and sides = 1 that have vertex angles from the set +Pi/9, +3*Pi/9, +5*Pi/9, +7*Pi/9, not counting rotations and reflections as distinct.


4




OFFSET

1,3


COMMENTS

Holes are excluded, i.e., the boundary path may nowhere touch or intersect itself.


LINKS

Table of n, a(n) for n=1..6.
Contest Organizers, Al Zimmermann's Programming Contests  Snakes on a Plane, Fall 2006.
Hugo Pfoertner, Illustration of polygons of perimeter <= 12.


CROSSREFS

Cf. A306179, A316195, A316197, A316198.
Sequence in context: A041126 A248289 A176823 * A300905 A008664 A107779
Adjacent sequences: A316196 A316197 A316198 * A316200 A316201 A316202


KEYWORD

nonn,walk,more


AUTHOR

Hugo Pfoertner, Jul 04 2018


STATUS

approved



