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
Links
- 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.
Extensions
Data corrected by Andrew Howroyd after observation by Gionata Neri, May 02 2020