id:A091496 - OEIS Search Results

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a(n) = ((5n)!/(n!(2n)!))(gamma(1+n/2)/gamma(1+5n/2)).

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1, 16, 630, 28672, 1385670, 69206016, 3528923580, 182536110080, 9540949030470, 502682972323840, 26651569523959380, 1420217179365703680, 75998432812419471900, 4081125953526124511232, 219813190240007470094520 (list; graph; listen)

	OFFSET	`0,2`
	FORMULA	`n(n-1)(2n-1)(2n-3)a(n)=20(5n-1)(5n-3)(5n-7)(5n-9)a(n-2).`
	PROGRAM	`(PARI) a(n)=16^nsum(i=0, 2n, binomial(i-1+(n-1)/2, i))`
	CROSSREFS	`Cf. A061163(n)=a(2n).` `Sequence in context: A016792 A077204 A159745 this_sequence A139166 A128048 A162546` `Adjacent sequences: A091493 A091494 A091495 this_sequence A091497 A091498 A091499`
	KEYWORD	`nonn`
	AUTHOR	`Michael Somos, Jan 15 2004`

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Last modified November 24 14:25 EST 2009. Contains 167438 sequences.

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