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A217822
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).
0
1, 9, 153, 3465, 92169, 2716425
OFFSET
1,2
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
STATUS
approved