A027617 - OEIS

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A027617

Number of permutations of n elements containing a 3-cycle.

0, 0, 0, 2, 8, 40, 200, 1400, 11200, 103040, 1030400, 11334400, 135766400, 1764963200, 24709484800, 370687116800 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,4`
	FORMULA	`n! * { 1 - sum[ k=0..floor(n/3) ] (-1)^k / (3^k * k!) }.`
	CROSSREFS	`Sequence in context: A181326 A186947 A071007 * A187071 A154626 A003305` `Adjacent sequences: A027614 A027615 A027616 * A027618 A027619 A027620`
	KEYWORD	`nonn`
	AUTHOR	`Joe Keane (jgk(AT)jgk.org)`

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Last modified February 17 13:14 EST 2012. Contains 206031 sequences.