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A116709
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Number of permutations of length n which avoid the patterns 2341, 4213.
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0
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1, 2, 6, 22, 86, 336, 1290, 4870, 18164, 67234, 247786, 911120, 3346618, 12286942, 45104548, 165573482, 607817410, 2231360192, 8191763970, 30074097062, 110410946820, 405353571346, 1488185247962, 5463619641904, 20058759689642
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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REFERENCES
| Kremer, Darla and Shiu, Wai Chee; Finite transition matrices for permutations avoiding pairs of length four patterns. Discrete Math. 268 (2003), 171-183. MR1983276 (2004b:05006). See Table 1.
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LINKS
| Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005.
Wikipedia, Permutation classes avoiding two patterns of length 4
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FORMULA
| G.f.: -x*(2*x^4-7*x^3+12*x^2-6*x+1)/(2*x^5-10*x^4+25*x^3-22*x^2+8*x-1).
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CROSSREFS
| Sequence in context: A165526 A165527 A165528 * A165529 A116710 A165530
Adjacent sequences: A116706 A116707 A116708 * A116710 A116711 A116712
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KEYWORD
| nonn,easy,changed
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AUTHOR
| Lara Pudwell (Lara.Pudwell(AT)valpo.edu), Feb 26 2006
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