

A217811


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


0




OFFSET

1,2


LINKS

Table of n, a(n) for n=1..9.
J. B. Lewis, Pattern Avoidance for Alternating Permutations and Reading Words of Tableaux, Ph. D. Dissertation, Department of Mathematics, MIT, 2012.


CROSSREFS

Cf. A181197, A217799A217830.
Sequence in context: A203358 A099666 A189444 * A217280 A236955 A064328
Adjacent sequences: A217808 A217809 A217810 * A217812 A217813 A217814


KEYWORD

nonn,more


AUTHOR

N. J. A. Sloane, Oct 13 2012


EXTENSIONS

a(7)a(9) from Lars Blomberg, Feb 17 2018


STATUS

approved



