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A239836
Number of ordered pairs of permutation functions f,g on a size n set where f(g(g(x))) = g(f(f(x))).
5
1, 1, 2, 6, 48, 360, 2880, 20160, 241920, 3265920
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OFFSET
0,3
LINKS
Table of n, a(n) for n=0..9.
CROSSREFS
Cf.
A000012
,
A000085
,
A000142
,
A088311
,
A053529
,
A001044
.
Sequence in context:
A281027
A271961
A362798
*
A052593
A358065
A052586
Adjacent sequences:
A239833
A239834
A239835
*
A239837
A239838
A239839
KEYWORD
nonn
,
more
AUTHOR
Chad Brewbaker
, Mar 27 2014
EXTENSIONS
a(8)-a(9) from
Giovanni Resta
, Mar 27 2014
STATUS
approved
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Last modified April 19 05:00 EDT 2024. Contains 371782 sequences. (Running on oeis4.)