A227657 Number of lattice paths from {3}^n to {0}^n using steps that decrement one component by 1 such that for each point (p_1,p_2,...,p_n) we have abs(p_{i}-p_{i+1}) <= 1.

1, 1, 8, 320, 33904, 7453320, 2940381648, 1891074940160, 1850957806329280, 2618225365541294080, 5140671157605632743040, 13563806648374752374753280, 46834662679585827124435729920, 206992078337280281738792256468480, 1149167357682367147108624229192064000

Offset

0,3

Links

Table of n, a(n) for n=0..14.

Example

a(2) = 2^3 = 8:
.     (2,3)       (1,2)       (0,1)
.    /     \     /     \     /     \
(3,3)       (2,2)       (1,1)       (0,0)
.    \     /     \     /     \     /
.     (3,2)       (2,1)       (1,0)

Crossrefs

Row n=3 of A227655.

Cf. A000079.

Sequence in context: A079504 A282621 A300189 * A057982 A308615 A041769

Adjacent sequences: A227654 A227655 A227656 * A227658 A227659 A227660

Keyword

nonn

Author

Alois P. Heinz, Jul 19 2013

Status

approved