A217801 Number of alternating permutations on 2n+1 letters that avoid a certain pattern of length 4 (see Lewis, 2012, Appendix, for precise definition).

1, 2, 12, 106, 1138, 13734, 179192, 2471958, 35557668

Offset

0,2

Links

Table of n, a(n) for n=0..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: A258230 A085867 A141133 * A036077 A275765 A184975

Adjacent sequences: A217798 A217799 A217800 * A217802 A217803 A217804

Keyword

nonn,more

Author

N. J. A. Sloane, Oct 12 2012

Extensions

a(6)-a(8) from Lars Blomberg, Jan 23 2018

Status

approved