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A261663 Number of equivalence classes of permutations avoiding the pattern {123}. 0
1, 1, 2, 4, 8, 19, 41, 98, 221, 526 (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: A018306 A139784 A247235 * A199694 A037444 A151526

Adjacent sequences:  A261660 A261661 A261662 * A261664 A261665 A261666

KEYWORD

nonn,more

AUTHOR

N. J. A. Sloane, Aug 30 2015

STATUS

approved

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Last modified March 26 14:18 EDT 2019. Contains 321497 sequences. (Running on oeis4.)