A116797 Number of permutations of length n which avoid the patterns 1432, 2134, 2314.

1, 2, 6, 21, 73, 241, 768, 2415, 7587, 23905, 75507, 238759, 755088, 2387570, 7548085, 23860518, 75425046, 238427267, 753705647, 2382596754, 7531821990, 23809446690, 75265885442, 237928695207, 752134317626, 2377628496399

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 98.

Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005.

Index entries for linear recurrences with constant coefficients, signature (6,-13,15,-9,7,-4)

Formula

G.f.: A(x) = -{(3x^5-4x^4+4x^3-7x^2+4x-1)x}/{4x^6-7x^5+9x^4-15x^3+13x^2-6x+1}

Crossrefs

Sequence in context: A116741 A116843 A116822 * A294804 A116744 A165521

Adjacent sequences: A116794 A116795 A116796 * A116798 A116799 A116800

Keyword

nonn,easy

Author

Lara Pudwell, Feb 26 2006

Status

approved