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A116751
Number of permutations of length n which avoid the patterns 2314, 2431, 3124.
0
1, 2, 6, 21, 75, 265, 929, 3249, 11362, 39746, 139060, 486549, 1702349, 5956172, 20839367, 72912441, 255104933, 892557394, 3122866871, 10926241348, 38228574601, 133753581322, 467975086412, 1637344431204, 5728716901208
OFFSET
1,2
FORMULA
G.f.: A(x) = -{x(x-1)^4}/{x^5-6x^4+13x^3-12x^2+6x-1}
CROSSREFS
Sequence in context: A116820 A369626 A294815 * A116823 A289597 A116743
KEYWORD
nonn,easy
AUTHOR
Lara Pudwell, Feb 26 2006
STATUS
approved