id:A116220 - OEIS Search Results

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If X_1,...,X_n is a partition of a 4n-set X into 4-blocks then a(n) is equal to the number of permutations f of X such that f(X_i)<>X_i, (i=1,...n).

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0, 39744, 476126208, 20876944084992, 2430394026897309696, 620098244484731975761920, 304784138698487640049544331264, 263072308376236973471661993731555328 (list; graph; listen)

	OFFSET	`1,2`
	LINKS	`Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets`
	FORMULA	`a(n)=sum((-24)^ibinomial(n,i)(4n-4i)!,i=0..n).`
	EXAMPLE	`a(5)=2430394026897309696`
	MAPLE	`a:=n->sum((-24)^ibinomial(n, i)(4n-4i)!, i=0..n).`
	CROSSREFS	`Adjacent sequences: A116217 A116218 A116219 this_sequence A116221 A116222 A116223` `Sequence in context: A088237 A031823 A004671 this_sequence A103809 A076670 A106772`
	KEYWORD	`nonn`
	AUTHOR	`Milan R. Janjic (agnus(AT)blic.net), Apr 09 2007`

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Last modified October 11 13:47 EDT 2008. Contains 144830 sequences.

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