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A217811
Number of alternating permutations on 2n letters that avoid a certain pattern of length 4 (see Lewis, 2012, Appendix, for precise definition).
0
1, 5, 61, 744, 10329, 157586, 2581722, 44710952, 809508414
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OFFSET
1,2
LINKS
Table of n, a(n) for n=1..9.
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:
A350973
A189444
A373106
*
A217280
A236955
A064328
Adjacent sequences:
A217808
A217809
A217810
*
A217812
A217813
A217814
KEYWORD
nonn
,
more
AUTHOR
N. J. A. Sloane
, Oct 13 2012
EXTENSIONS
a(7)-a(9) from
Lars Blomberg
, Feb 17 2018
STATUS
approved
