A116816 Number of permutations of length n which avoid the patterns 2314, 3124, 4312.

1, 2, 6, 21, 75, 260, 869, 2817, 8920, 27745, 85113, 258256, 776717, 2319093, 6882432, 20321017, 59738793, 174960544, 510756501, 1486819229, 4317417984, 12509488161, 36175413601, 104433440896, 301022300573, 866485007957

Offset

1,2

Links

Table of n, a(n) for n=1..26.

D. Callan, T. Mansour, Enumeration of small Wilf classes avoiding 1324 and two other 4-letter patterns, arXiv:1705.00933 [math.CO] (2017), Table 2 No 154 and 155.

Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005.

Index entries for linear recurrences with constant coefficients, signature (8,-24,35,-28,12,-2)

Formula

G.f.: A(x) = -{(2x^5-9x^4+14x^3-14x^2+6x-1)x}/{(x-1)(x^2-3x+1)(2x^3-4x^2+4x-1)}

Crossrefs

Sequence in context: A294807 A294771 A294814 * A116742 A116746 A116806

Adjacent sequences: A116813 A116814 A116815 * A116817 A116818 A116819

Keyword

nonn,easy

Author

Lara Pudwell, Feb 26 2006

Status

approved