login
The OEIS is supported by
the many generous donors to the OEIS Foundation
.
Hints
(Greetings from
The On-Line Encyclopedia of Integer Sequences
!)
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
Lookup
|
Welcome
|
Wiki
|
Register
|
Music
|
Plot 2
|
Demos
|
Index
|
Browse
|
More
|
WebCam
Contribute new seq. or comment
|
Format
|
Style Sheet
|
Transforms
|
Superseeker
|
Recents
The OEIS Community
| Maintained by
The OEIS Foundation Inc.
License Agreements, Terms of Use, Privacy Policy.
.
Last modified April 23 12:27 EDT 2024. Contains 371912 sequences. (Running on oeis4.)