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
Links
- J. B. Lewis, Pattern Avoidance for Alternating Permutations and Reading Words of Tableaux, Ph. D. Dissertation, Department of Mathematics, MIT, 2012.
Extensions
a(7)-a(8) from Lars Blomberg, Feb 28 2018