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A116714 Number of permutations of length n that avoid the patterns 321, 1342, 4123. 1
1, 2, 5, 12, 24, 46, 87, 162, 300, 554, 1021, 1880, 3460, 6366, 11711, 21542, 39624, 72882, 134053, 246564, 453504, 834126, 1534199, 2821834, 5190164, 9546202, 17558205, 32294576, 59398988, 109251774, 200945343, 369596110, 679793232 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..33.

Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005.

Index entries for linear recurrences with constant coefficients, signature (2,0,0,-1).

FORMULA

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

MAPLE

A116714 := proc(n) coeftayl(x*(x^4+2*x^3+x^2+1)/(x-1)/(x^3+x^2+x-1), x=0, n) ; end: seq(A116714(n), n=1..50) ; # R. J. Mathar, Jan 22 2008

CROSSREFS

Sequence in context: A192981 A116713 A261369 * A023615 A320235 A034483

Adjacent sequences:  A116711 A116712 A116713 * A116715 A116716 A116717

KEYWORD

nonn,easy

AUTHOR

Lara Pudwell, Feb 26 2006

STATUS

approved

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Last modified February 22 23:44 EST 2020. Contains 332157 sequences. (Running on oeis4.)