A217817 Number of alternating permutations on 2n letters that avoid a certain pattern of length 5 (see Lewis, 2012, Appendix, for precise definition).

1, 5, 56, 997, 23653, 679810, 22394962, 816872290

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: A367155 A298689 A357392 * A217818 A217819 A132618

Adjacent sequences: A217814 A217815 A217816 * A217818 A217819 A217820

Keyword

nonn,more

Author

N. J. A. Sloane, Oct 13 2012

Extensions

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

Status

approved