A217820 Number of alternating permutations on 2n letters that avoid a certain pattern of length 5 (see Lewis, 2012, Appendix, for precise definition).

1, 5, 61, 1194, 30802, 953088, 33563745, 1302192441

Offset

1,2

Links

Table of n, a(n) for n=1..8.

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: A298695 A352238 A349715 * A217821 A371371 A009825

Adjacent sequences: A217817 A217818 A217819 * A217821 A217822 A217823

Keyword

nonn,more

Author

N. J. A. Sloane, Oct 13 2012

Extensions

a(7)-a(8) from Lars Blomberg, Feb 28 2018

Status

approved