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A115254 Diagonal sums of correlation triangle for Catalan numbers. 1
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 (list; graph; refs; listen; history; text; internal format)
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 A090378 A007180

Adjacent sequences:  A115251 A115252 A115253 * A115255 A115256 A115257

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Jan 18 2006

STATUS

approved

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Last modified February 16 03:26 EST 2019. Contains 320140 sequences. (Running on oeis4.)