A116748 Number of permutations of length n which avoid the patterns 2314, 4132, 4321.

1, 2, 6, 21, 72, 228, 678, 1929, 5307, 14203, 37133, 95179, 239942, 596587, 1466529, 3571386, 8630575, 20725008, 49509197, 117762285, 279109649, 659555800, 1554707004, 3657127140, 8587557316, 20135214390, 47151860695, 110301150860

Offset

1,2

Links

Table of n, a(n) for n=1..28.

D. Callan, T. Mansour, Enumeration of small Wilf classes avoiding 1324 and two other 4-letter patterns, arXiv:1705.00933 (2017), Table 2 No 44.

Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005.

Index entries for linear recurrences with constant coefficients, signature (10,-43,105,-162,166,-115,53,-15,2)

Formula

G.f.: A(x) = {x(x^9-8x^8+24x^7-44x^6+61x^5-72x^4+58x^3-29x^2+8x-1)}/{(2x-1)(x-1)^5(x^3-2x^2+3x-1)}

Crossrefs

Sequence in context: A116791 A116775 A116786 * A116812 A116830 A116747

Adjacent sequences: A116745 A116746 A116747 * A116749 A116750 A116751

Keyword

nonn,easy

Author

Lara Pudwell, Feb 26 2006

Status

approved