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A234843
Number of commutative inverse semigroups of order n.
3
1, 2, 5, 16, 51, 201, 877, 4443, 25284, 161698, 1145508, 8910291, 75373563, 687950735, 6727985390
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OFFSET
1,2
LINKS
Table of n, a(n) for n=1..15.
Martin E. Malandro,
Enumeration of finite inverse semigroups
, arXiv:1312.7192 [math.CO]
CROSSREFS
Cf.
A001428
(inverse semigroups),
A234844
(inverse monoids),
A234845
(commutative inverse monoids).
Sequence in context:
A268213
A231357
A303477
*
A011819
A148390
A232317
Adjacent sequences:
A234840
A234841
A234842
*
A234844
A234845
A234846
KEYWORD
nonn
,
hard
,
more
AUTHOR
Joerg Arndt
, Dec 31 2013
STATUS
approved
