id:A116730 - OEIS Search Results

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Number of permutations of length n which avoid the patterns 321, 1342, 1423.

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1, 2, 5, 12, 25, 48, 87, 152, 259, 434, 719, 1182, 1933, 3150, 5121, 8312, 13477, 21836, 35363, 57252, 92671, 149982, 242715, 392762, 635545, 1028378, 1663997, 2692452, 4356529, 7049064, 11405679, 18454832, 29860603, 48315530, 78176231, 126491862 (list; graph; listen)

	OFFSET	`1,2`
	LINKS	`Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005.`
	FORMULA	`G.f.: A(x) = -{x(2x^3+x^2-x+1)}/{(x-1)^2(x^2+x-1)}` `a(n) = 2*A000045(n+3)-3n-2. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 05 2008]`
	CROSSREFS	`Sequence in context: A116720 A116731 A116722 this_sequence A067331 A116734 A101836` `Adjacent sequences: A116727 A116728 A116729 this_sequence A116731 A116732 A116733`
	KEYWORD	`nonn,easy`
	AUTHOR	`Lara Pudwell (Lara.Pudwell(AT)valpo.edu), Feb 26 2006`
	EXTENSIONS	`Extended beyond a(30) by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 05 2008`

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

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