A116794 Number of permutations of length n which avoid the patterns 2341, 3214, 4132.

1, 2, 6, 21, 70, 210, 589, 1592, 4218, 11069, 28932, 75528, 197165, 514920, 1345484, 3517427, 9198984, 24064848, 62968211, 164789078, 431305300, 1128953923, 2955237882, 7736173110, 20252201791, 53018445686, 138799480530

Offset

1,2

Links

Table of n, a(n) for n=1..27.

D. Callan, T. Mansour, Enumeration of small Wilf classes avoiding 1324 and two other 4-letter patterns, arXiv:1705.00933 (2017), Table 2 No 16.

Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005.

Index entries for linear recurrences with constant coefficients, signature (7,-18,21,-12,7,-8,5,-1).

Formula

G.f.: A(x) = -{x(2x^8-4x^6+11x^5-x^4+6x^3-10x^2+5x-1)}/{(x^3+x^2+x-1)(x^2-3x+1)(x-1)^3}

Crossrefs

Sequence in context: A116832 A116811 A294718 * A294719 A116795 A116766

Adjacent sequences: A116791 A116792 A116793 * A116795 A116796 A116797

Keyword

nonn,easy

Author

Lara Pudwell, Feb 26 2006

Status

approved