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A116713
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Number of permutations of length n which avoid the patterns 123, 2431, 4132.
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1
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1, 2, 5, 12, 24, 45, 83, 154, 290, 555, 1077, 2112, 4172, 8281, 16487, 32886, 65670, 131223, 262313, 524476, 1048784, 2097381, 4194555, 8388882, 16777514, 33554755, 67109213, 134218104, 268435860, 536871345, 1073742287, 2147484142
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005.
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FORMULA
| G.f.: A(x) = {(2x^5-3x^4-2x^3+4x^2-3x+1)x}/{(x-1)^3(2x-1)}
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MAPLE
| A116713 := proc(n) coeftayl(x*(2*x^5-3*x^4-2*x^3+4*x^2-3*x+1)/(x-1)^3/(2*x-1), x=0, n) ; end: seq(A116713(n), n=1..50) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 23 2008
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CROSSREFS
| Sequence in context: A116733 A116721 A192981 * A116714 A023615 A034483
Adjacent sequences: A116710 A116711 A116712 * A116714 A116715 A116716
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KEYWORD
| nonn,easy
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AUTHOR
| Lara Pudwell (Lara.Pudwell(AT)valpo.edu), Feb 26 2006
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EXTENSIONS
| More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 23 2008
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