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A058117 Number of commutative semigroups of order n with 1 idempotent. 1
1, 2, 5, 16, 62, 342, 3435 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..7.

Index entries for sequences related to semigroups

CROSSREFS

Column 1 of A058116.

Sequence in context: A144188 A157314 A159603 * A007124 A112951 A124470

Adjacent sequences:  A058114 A058115 A058116 * A058118 A058119 A058120

KEYWORD

nonn,hard

AUTHOR

Christian G. Bower, Nov 09 2000

STATUS

approved

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Last modified August 27 17:19 EDT 2015. Contains 261095 sequences.