A107113 Diagonal sums of A107111, viewed as a number triangle.

1, 1, 2, 3, 6, 11, 24, 52, 125, 307, 809, 2190, 6249, 18348, 56016, 176272, 571113, 1906091, 6517283, 22879944, 82144248, 301617448, 1131401427, 4327790902, 16886037207, 67073179408, 271242546501, 1115489848809, 4662462489619

Offset

0,3

Links

Table of n, a(n) for n=0..28.

Formula

a(n)=sum{k=0..floor(n/2), sum{j=0..k, binomial((n-2k)(k+1), k-j)*binomial(k+j, j)}/(k+1)}

Crossrefs

Sequence in context: A122852 A192573 A284994 * A156807 A032256 A324765

Adjacent sequences: A107110 A107111 A107112 * A107114 A107115 A107116

Keyword

easy,nonn

Author

Paul Barry, May 12 2005

Status

approved