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A217823
Number of permutations of length 3n with descent set {3, 6, ...} that avoid a certain pattern of length 4 or 5 (see Lewis, 2012, Appendix, for precise definition).
1
1, 1, 9, 153, 3579, 101630, 3288871
OFFSET
0,3
COMMENTS
Is this the same sequence as A361190?
LINKS
J. B. Lewis, Pattern Avoidance for Alternating Permutations and Reading Words of Tableaux, Ph. D. Dissertation, Department of Mathematics, MIT, 2012.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Oct 13 2012
EXTENSIONS
a(5)-a(6) from Lars Blomberg, Mar 09 2018
a(0)=1 prepended by Alois P. Heinz, Jul 31 2023
STATUS
approved