A105369 - OEIS

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A105369

Expansion of ((1+x)^3-x^3)/((1+x)^5-x^5).

1, -2, 3, -5, 10, -20, 35, -50, 50, 0, -175, 625, -1625, 3625, -7250, 13125, -21250, 29375, -29375, 0, 106250, -384375, 1006250, -2250000, 4500000, -8140625, 13171875, -18203125, 18203125, 0, -65859375, 238281250, -623828125, 1394921875, -2789843750, 5046875000, -8166015625 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	COMMENTS	`Consecutive pair sums gives A105370.`
	FORMULA	`G.f.: (1+3x+3x^2)/(1+5x+10x^2+10x^3+5x^4); a(n)=2sqrt(5)(5/2-sqrt(5)/2)^(n/2)cos(7pin/10+pi/5)/5+ 2sqrt(5)(5/2+sqrt(5)/2)^(n/2)cos(9pin/10+2pi/5)/5`
	CROSSREFS	`Sequence in context: A054317 A065840 A093785 * A047101 A057755 A076834` `Adjacent sequences: A105366 A105367 A105368 * A105370 A105371 A105372`
	KEYWORD	`easy,sign`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Apr 01 2005`

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Last modified February 16 01:56 EST 2012. Contains 205860 sequences.