A227673 Number of lattice paths from {n}^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, 4, 320, 1281696, 482913033152, 27297846037161958056, 337320253484345016223956919936, 1248760044848501400078426452469652899962528, 1817025580455577353700768095528219275036151622984555026720

Offset

0,3

Links

Table of n, a(n) for n=0..9.

Example

a(0) = 1: () .
a(1) = 1: (1)-(0) .
.               (1,2)       (0,1)
.              /     \     /     \
a(2) = 4: (2,2)       (1,1)       (0,0) .
.              \     /     \     /
.               (2,1)       (1,0)

Crossrefs

Main diagonal of A227655.

Sequence in context: A280792 A027512 A153220 * A203479 A034226 A186163

Adjacent sequences: A227670 A227671 A227672 * A227674 A227675 A227676

Keyword

nonn

Author

Alois P. Heinz, Jul 19 2013

Status

approved