A217810 Number of alternating permutations on 2n letters that avoid a certain pattern of length 4 (see Lewis, 2012, Appendix, for precise definition).

1, 5, 42, 454, 5680, 78129

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. See Table A.2.

Crossrefs

Cf. A181197, A217799-A217830.

Sequence in context: A024492 A217805 A217808 * A151334 A005789 A217809

Adjacent sequences: A217807 A217808 A217809 * A217811 A217812 A217813

Keyword

nonn,more

Author

N. J. A. Sloane, Oct 13 2012

Extensions

Data corrected by Andrew Howroyd after observation by Gionata Neri, May 02 2020

Status

approved