A115254 Diagonal sums of correlation triangle for Catalan numbers.

1, 1, 3, 7, 19, 52, 162, 505, 1666, 5576, 19135, 66494, 234316, 833620, 2992817, 10822802, 39395434, 144207387, 530534468, 1960521470, 7273963575, 27085625086, 101188629692, 379160330195, 1424634014730, 5366319233160

Offset

0,3

Comments

Diagonal sums of number triangle A115253.

Convolution of A161006 and A079978. - R. J. Mathar, Oct 04 2014

Links

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

Formula

G.f.: c(x)c(x^2)/(1-x^3) where c(x) is the g.f. of A000108; a(n)=sum{k=0..floor(n/2), sum{j=0..n-k, [j<=k]*C(k-j)[j<=n-2k]*C(n-2k-j)}}.

Crossrefs

Sequence in context: A146597 A320734 A259812 * A222324 A007180 A090378

Adjacent sequences: A115251 A115252 A115253 * A115255 A115256 A115257

Keyword

easy,nonn

Author

Paul Barry, Jan 18 2006

Status

approved