A167402 Number of n-step walks on square lattice, self-avoiding until the last step.

0, 0, 4, 12, 44, 116, 356, 948, 2772, 7396, 20972, 56108, 156236, 418228, 1151556, 3081180, 8421052, 22514652, 61207972, 163518308, 442769316, 1181982628, 3190663628, 8511628124, 22920057932, 61104234356, 164212633412

Offset

0,3

Comments

A001411(n)=4^n-(a(n)+4*(a(n-1)+4*(a(n-2)+...)))

Links

Table of n, a(n) for n=0..26.

Formula

a(n) = 4*A001411(n-1)-A001411(n), n>0. [From Vladeta Jovovic, Nov 02 2009]

Crossrefs

See references given for A001411.

Sequence in context: A149358 A149359 A259223 * A320643 A060897 A005190

Adjacent sequences: A167399 A167400 A167401 * A167403 A167404 A167405

Keyword

nonn

Author

Vadim Sheikhman (vvsshh(AT)gmail.com), Nov 02 2009

Extensions

More terms from Vladeta Jovovic, Nov 02 2009

Status

approved