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A239757
Number of pairs of functions (f,g) from a set of n elements into itself satisfying f(g(g(x))) = g(f(f(x))).
0
1, 1, 8, 141, 4192, 178225, 10218096, 762401773
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OFFSET
0,3
LINKS
Table of n, a(n) for n=0..7.
CROSSREFS
Cf.
A000248
,
A000949
.
Sequence in context:
A224735
A090931
A367199
*
A295242
A305763
A180357
Adjacent sequences:
A239754
A239755
A239756
*
A239758
A239759
A239760
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 25 03:15 EDT 2024. Contains 371964 sequences. (Running on oeis4.)