A128416 - OEIS

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A128416

Expansion of (1-4x^2)/(1+4x+3x^2).

1, -4, 9, -24, 69, -204, 609, -1824, 5469, -16404, 49209, -147624, 442869, -1328604, 3985809, -11957424, 35872269, -107616804, 322850409, -968551224, 2905653669, -8716961004, 26150883009, -78452649024, 235357947069 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	COMMENTS	`Diagonal sums of number triangle A128414.`
	FORMULA	`The absolute values of the terms satisfy a(n)=3(a(n-1)-1) a(1)=4 [From Tamas Kalmar-Nagy (integers(AT)kalmarnagy.com), Sep 17 2010]`
	CROSSREFS	`Sequence in context: A077922 A081149 A059507 * A175121 A133905 A131826` `Adjacent sequences: A128413 A128414 A128415 * A128417 A128418 A128419`
	KEYWORD	`easy,sign`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Mar 02 2007`

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Last modified February 14 00:47 EST 2012. Contains 205567 sequences.