id:A116733 - OEIS Search Results

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Number of permutations of length n which avoid the patterns 321, 1324, 2341.

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1, 2, 5, 12, 24, 41, 63, 90, 122, 159, 201, 248, 300, 357, 419, 486, 558, 635, 717, 804, 896, 993, 1095, 1202, 1314, 1431, 1553, 1680, 1812, 1949, 2091, 2238, 2390, 2547, 2709, 2876, 3048, 3225, 3407, 3594, 3786, 3983, 4185, 4392, 4604, 4821, 5043, 5270 (list; graph; listen)

	OFFSET	`1,2`
	LINKS	`Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005.`
	FORMULA	`G.f.: A(x) = -{x(x^4+2x^3+2x^2-x+1)}/{(x-1)^3}` `For n >= 3, a(n) = (5n^2 - 21n + 28)/2. - Franklin T. Adams-Watters, Sep 16 2006`
	CROSSREFS	`Sequence in context: A096376 A112287 A127787 this_sequence A116721 A116713 A116714` `Adjacent sequences: A116730 A116731 A116732 this_sequence A116734 A116735 A116736`
	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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