A086905 - OEIS

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A086905

Sum_{k=0..n} (-1)^(n-k)*binomial(k,floor(k/2)).

1, 0, 2, 1, 5, 5, 15, 20, 50, 76, 176, 286, 638, 1078, 2354, 4081, 8789, 15521, 33099, 59279, 125477, 227239, 478193, 873885, 1830271, 3370029, 7030571, 13027729, 27088871, 50469889, 104647631, 195892564, 405187826, 761615284, 1571990936 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,3`
	COMMENTS	`Kn{\"o}del walks starting and ending at 0, with n steps.`
	LINKS	`H. Prodinger, The Kernel Method: a collection of examples`
	FORMULA	`G.f.: (sqrt((1+2x)/(1-2x))-1)/2/x/(1+x).`
	CROSSREFS	`Cf. A036256, A001405.` `First column of triangle A101491.` `Sequence in context: A119245 A128731 A129157 * A167638 A184234 A054651` `Adjacent sequences: A086902 A086903 A086904 * A086906 A086907 A086908`
	KEYWORD	`nonn`
	AUTHOR	`Vladeta Jovovic (vladeta(AT)eunet.rs), Sep 19 2003`

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Last modified February 17 23:49 EST 2012. Contains 206085 sequences.