A217830 - OEIS

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A217830

Number of permutations of length 3n with descent set {3, 6, ...} that avoid a certain pattern of length 4 or 5 (see Lewis, 2012, Appendix, for precise definition).

1, 19, 1513, 211425, 40607753, 9694117094

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..6.

J. B. Lewis, Pattern Avoidance for Alternating Permutations and Reading Words of Tableaux, Ph. D. Dissertation, Department of Mathematics, MIT, 2012.

CROSSREFS

Cf. A181197, A217799-A217830.

Sequence in context: A237429 A177611 A051847 * A002115 A223498 A352465

Adjacent sequences: A217827 A217828 A217829 * A217831 A217832 A217833

KEYWORD

nonn,more

AUTHOR

N. J. A. Sloane, Oct 13 2012

EXTENSIONS

a(5)-a(6) from Lars Blomberg, Mar 09 2018

STATUS

approved