A115254 - OEIS

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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 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,3`
	COMMENTS	`Diagonal sums of number triangle A115253.`
	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: A135052 A198305 A146597 * A090378 A007180 A059506` `Adjacent sequences: A115251 A115252 A115253 * A115255 A115256 A115257`
	KEYWORD	`easy,nonn`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Jan 18 2006`

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Last modified February 17 14:50 EST 2012. Contains 206050 sequences.