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URL: https://oeis.org/A116741

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A116741

Number of permutations of length n which avoid the patterns 1342, 2314, 4213.

0

1, 2, 6, 21, 73, 241, 757, 2288, 6724, 19365, 54959, 154303, 429733, 1189430, 3276306, 8990037, 24591349, 67093357, 182653717, 496322396, 1346450176, 3647459397, 9868036571, 26666447611, 71984395333, 194127819746

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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 95.

Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005.

Index entries for linear recurrences with constant coefficients, signature (10,-40,82,-92,56,-17,2).

FORMULA

G.f.: A(x) = -{(2x^6-13x^5+31x^4-41x^3+26x^2-8x+1)x}/{(2x-1)(x^2-3x+1)^2(x-1)^2}

CROSSREFS

Sequence in context: A116787 A294803 A116773 * A116843 A116822 A116797

Adjacent sequences: A116738 A116739 A116740 * A116742 A116743 A116744

KEYWORD

nonn,easy

AUTHOR

Lara Pudwell, Feb 26 2006

STATUS

approved