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A239755
Number of pairs of functions (f,g) from a set of n elements into itself satisfying f(g(x)) = g(f(f(x))).
0
1, 1, 8, 123, 2776, 86265, 3498336, 179365669
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OFFSET
0,3
LINKS
Table of n, a(n) for n=0..7.
CROSSREFS
Cf.
A000248
,
A000949
.
Sequence in context:
A349525
A240477
A195247
*
A264408
A364985
A120957
Adjacent sequences:
A239752
A239753
A239754
*
A239756
A239757
A239758
KEYWORD
nonn
,
more
AUTHOR
Chad Brewbaker
, Mar 26 2014
EXTENSIONS
a(6)-a(7) from
Giovanni Resta
, Mar 28 2014
STATUS
approved
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Last modified April 23 10:07 EDT 2024. Contains 371905 sequences. (Running on oeis4.)