id:A137646 - OEIS Search Results

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a(n) = Sum_{k=0..n} C(k*(k+1)/2, k) * C(k*(k+1)/2, n-k).

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1, 1, 4, 29, 339, 5406, 109159, 2664399, 76219485, 2499425650, 92402751894, 3801481338219, 172231146665554, 8520038462375370, 456913020454609665, 26402792230144908683, 1635399597258002744628, 108090275300425856404653 (list; graph; listen)

	OFFSET	`0,3`
	PROGRAM	`(PARI) a(n)=sum(k=0, n, binomial(k(k+1)/2, k)binomial(k*(k+1)/2, n-k))`
	CROSSREFS	`Sequence in context: A028853 A118795 A099700 this_sequence A000798 A135485 A162287` `Adjacent sequences: A137643 A137644 A137645 this_sequence A137647 A137648 A137649`
	KEYWORD	`nonn`
	AUTHOR	`Paul D. Hanna (pauldhanna(AT)juno.com), Jan 31 2008`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

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