A109957 - OEIS

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A109957

Diagonal sums of number triangle A109956.

1, -1, 4, -16, 74, -368, 1926, -10455, 58333, -332489, 1927761, -11334128, 67416570, -404956315, 2453012916, -14967587873, 91910798556, -567566697627, 3522334450512, -21957276973619, 137425078658354, -863229921626723, 5440215989173113, -34388244134246836 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,3`
	FORMULA	`G.f. : g/(1-f) where f/(1-f)^3=x and g=1-f; a(n)=(-1)^nsum{k=0..floor(n/2), ((3k+1)/(2n-k+1))binomial(3n-3k, n-2k)}.`
	CROSSREFS	`Sequence in context: A096244 A030131 A091530 * A101205 A204772 A050540` `Adjacent sequences: A109954 A109955 A109956 * A109958 A109959 A109960`
	KEYWORD	`easy,sign`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Jul 06 2005`

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Last modified February 17 00:09 EST 2012. Contains 205978 sequences.