id:A087137 - OEIS Search Results

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a(n) is the number of permutations in the symmetric group S_n that contain an odd cycle.

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1, 1, 6, 15, 120, 495, 5040, 29295, 362880, 2735775, 39916800, 370945575, 6227020800, 68916822975, 1307674368000, 16813959537375, 355687428096000, 5214921734397375, 121645100408832000, 2004231846526284375 (list; graph; listen)

	OFFSET	`1,3`
	FORMULA	`E.g.f.: 1/(1-x)-1/sqrt(1-x^2). If n is odd then a(n) = n! else a(n) = n!-((n-1)!!)^2.`
	CROSSREFS	`Cf. A059838, A001818.` `Sequence in context: A013222 A013228 A133472 this_sequence A056317 A129421 A013227` `Adjacent sequences: A087134 A087135 A087136 this_sequence A087138 A087139 A087140`
	KEYWORD	`nonn`
	AUTHOR	`Yuval Dekel (dekelyuval(AT)hotmail.com), Oct 18 2003`
	EXTENSIONS	`Formulae and more terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Oct 31 2003`

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Last modified December 18 21:37 EST 2009. Contains 171024 sequences.

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