A306180 Number of unrooted self-avoiding walks with n steps that can make turns from the set 0, +-Pi/5, +-2*Pi/5, +-3*Pi/5, +-4*Pi/5.

1, 5, 23, 169, 1233, 9551

Offset

1,2

Comments

The turning angles are those of the regular decagon, with one vertex corresponding to the forbidden U-turn. The path may neither intersect nor touch itself anywhere.

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 walks of lengths <= 3.

Crossrefs

Cf. A266925, A037245, A306175, A151541, A306177, A306178, A306179, A306181, A306182.

Sequence in context: A178383 A377584 A167576 * A308443 A116151 A371651

Adjacent sequences: A306177 A306178 A306179 * A306181 A306182 A306183

Keyword

nonn,walk,more

Author

Hugo Pfoertner, Jun 23 2018

Status

approved