A113312 - OEIS

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A113312

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

1, 2, 3, 3, 4, 3, 5, 2, 7, -1, 12, -9, 25, -30, 59, -85, 148, -229, 381, -606, 991, -1593, 2588, -4177, 6769, -10942, 17715, -28653, 46372, -75021, 121397, -196414, 317815, -514225, 832044, -1346265, 2178313, -3524574, 5702891, -9227461, 14930356, -24157813, 39088173, -63245982, 102334159 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	COMMENTS	`Diagonal sums of A113310.`
	FORMULA	`a(n)=2a(n-2)-a(n-3); a(n)=sum{k=0..floor(n/2), sum{i=0..n-2k, (-1)^i*C(i+k-2, i)}}.`
	CROSSREFS	`Sequence in context: A179846 A086925 A088858 * A053475 A140605 A049878` `Adjacent sequences: A113309 A113310 A113311 * A113313 A113314 A113315`
	KEYWORD	`easy,sign`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Oct 25 2005`

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Last modified February 13 08:12 EST 2012. Contains 205451 sequences.