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A060158
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Number of permutations of [n] with 4 sequences.
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4
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0, 0, 0, 0, 0, 32, 300, 1852, 9576, 45096, 201060, 866324, 3650592, 15154240, 62260380, 253939116, 1030367448, 4165106264, 16790875860, 67553807428, 271383782544, 1089035545968, 4366631897100, 17497971562460, 70086163646280, 280627369334152, 1123357369925700
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OFFSET
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0,6
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REFERENCES
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L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 261.
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LINKS
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FORMULA
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a(n) = 2n - 7 + (6-n)*2^(n-1) - 3^n + 4^(n-1).
G.f.: 4*x^5*(8-29*x+24*x^2)/((1-4*x)*(1-3*x)*(1-2*x)^2*(1-x)^2).
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MAPLE
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n4 := n->2*n-7+(6-n)*2^(n-1)-3^n+4^(n-1); seq(n4(i), i=5..27);
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MATHEMATICA
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Join[{0, 0}, LinearRecurrence[{13, -67, 175, -244, 172, -48}, {0, 0, 0, 32, 300, 1852}, 25]] (* Jean-François Alcover, Sep 02 2018 *)
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PROG
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(PARI) { for (n=0, 200, if (n<2, a=0, a=2*n - 7 + (6 - n)*2^(n - 1) - 3^n + 4^(n - 1)); write("b060158.txt", n, " ", a); ) } \\ Harry J. Smith, Jul 02 2009
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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Barbara Haas Margolius (margolius(AT)math.csuohio.edu), Mar 12 2001
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EXTENSIONS
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STATUS
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approved
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