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 A116708 Number of permutations of length n which avoid the patterns 2314, 4321. 1
 1, 2, 6, 22, 86, 330, 1198, 4087, 13185, 40619, 120636, 348197, 983073, 2728722, 7475575, 20274288, 54558291, 145933414, 388520823, 1030601705, 2726043970, 7194657991, 18955376065, 49872709551, 131077883030, 344216450494, 903332924312, 2369406020786 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Colin Barker, Table of n, a(n) for n = 1..1000 Darla Kremer and Wai Chee Shiu, Finite transition matrices for permutations avoiding pairs of length four patterns, Discrete Math. 268 (2003), 171-183. MR1983276 (2004b:05006). See Table 1. Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005. Wikipedia, Permutation classes avoiding two patterns of length 4 Index entries for linear recurrences with constant coefficients, signature (13,-74,243,-510,715,-678,429,-173,40,-4). FORMULA G.f.: -x*(4*x^9-29*x^8+108*x^7-234*x^6+313*x^5-268*x^4+151*x^3-54*x^2+11*x-1) / ((x-1)^6*(2*x-1)^2*(x^2-3*x+1)). PROG (PARI) Vec((1 - 11*x + 54*x^2 - 151*x^3 + 268*x^4 - 313*x^5 + 234*x^6 - 108*x^7 + 29*x^8 - 4*x^9) / ((1 - x)^6*(1 - 2*x)^2*(1 - 3*x + x^2)) + O(x^30)) \\ Colin Barker, Oct 20 2017 CROSSREFS Sequence in context: A079105 A079104 A116705 * A116706 A165524 A165525 Adjacent sequences: A116705 A116706 A116707 * A116709 A116710 A116711 KEYWORD nonn,easy,changed AUTHOR Lara Pudwell, Feb 26 2006 STATUS approved

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Last modified September 12 22:49 EDT 2024. Contains 375855 sequences. (Running on oeis4.)