A109248 - OEIS

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A109248

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

1, -1, -1, -2, 0, -1, 2, -1, 3, -3, 4, -6, 7, -10, 13, -17, 23, -30, 40, -53, 70, -93, 123, -163, 216, -286, 379, -502, 665, -881, 1167, -1546, 2048, -2713, 3594, -4761, 6307, -8355, 11068, -14662, 19423, -25730, 34085, -45153, 59815, -79238, 104968, -139053, 184206, -244021, 323259, -428227, 567280 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,4`
	COMMENTS	`Diagonal sums of Riordan array (1-x-2x^2,x(1-x)), A109246.`
	FORMULA	`a(n)=a(n-2)-a(n-3)`
	CROSSREFS	`Sequence in context: A131331 A020513 A029276 * A131866 A036862 A094238` `Adjacent sequences: A109245 A109246 A109247 * A109249 A109250 A109251`
	KEYWORD	`easy,sign`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Jun 23 2005`

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Last modified February 16 05:51 EST 2012. Contains 205860 sequences.