id:A116770 - OEIS Search Results

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Number of permutations of length n which avoid the patterns 1243, 1342, 4312.

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1, 2, 6, 21, 73, 234, 691, 1910, 5019, 12690, 31147, 74694, 175843, 407810, 934179, 2117958, 4759915, 10617234, 23527867, 51839462, 113639955, 247988802, 538968691, 1167065766, 2518680283, 5419041554, 11626611531, 24880612230 (list; graph; listen)

	OFFSET	`1,2`
	LINKS	`Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005.`
	FORMULA	`G.f.: A(x) = {x(3x^6-12x^5+22x^4-30x^3+21x^2-7x+1)}/{(2x-1)^3(x-1)^3}` `a(n)=2^n*(-99/16+29n/32+3n^2/32)+n^2+4n+6, n>1. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 05 2008]`
	CROSSREFS	`Sequence in context: A116789 A116783 A116739 this_sequence A116753 A116757 A116839` `Adjacent sequences: A116767 A116768 A116769 this_sequence A116771 A116772 A116773`
	KEYWORD	`nonn,easy`
	AUTHOR	`Lara Pudwell (Lara.Pudwell(AT)valpo.edu), Feb 26 2006`

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Last modified November 18 20:14 EST 2008. Contains 147244 sequences.

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