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A261664 Number of equivalence classes of permutations avoiding the pattern {231}. 0
1, 1, 2, 4, 9, 21, 50, 121, 296, 729 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
It seems that there is no known g.f.
LINKS
Table of n, a(n) for n=0..9.
J.-L. Baril, T. Mansour, A. Petrossian, Equivalence classes of permutations modulo excedances, Journal of Combinatorics, Volume 5 (2014), Number 4, doi:10.4310/JOC.2014.v5.n4.a4.
CROSSREFS
Sequence in context: A171842 A296201 A027826 * A355043 A091964 A092423
Adjacent sequences: A261661 A261662 A261663 * A261665 A261666 A261667
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Aug 30 2015
STATUS
approved

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Last modified May 15 17:39 EDT 2024. Contains 372548 sequences. (Running on oeis4.)