A107269 Diagonal sums of A107267, viewed as a number triangle.

1, 0, 1, 1, 3, 6, 16, 44, 136, 457, 1669, 6547, 27334, 120465, 557094, 2692528, 13564940, 71102869, 387132791, 2185813423, 12775466408, 77154694819, 480630407368, 3083443893896, 20344187534051, 137884769704754

Offset

0,5

Links

Table of n, a(n) for n=0..25.

Formula

a(n)=sum{k=0..n, sum{j=0..n-2k, (1/(j+1))C(j+1, n-2k-j+1)C(n-2k, j)k^j}}

Crossrefs

Sequence in context: A274295 A192676 A202846 * A333026 A086811 A106361

Adjacent sequences: A107266 A107267 A107268 * A107270 A107271 A107272

Keyword

easy,nonn

Author

Paul Barry, May 15 2005

Status

approved