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A058109 Semigroups of order n with 1 idempotent. 1
1, 2, 5, 20, 171, 5284, 1224331 (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 A058108.

Sequence in context: A184730 A181076 A156871 * A005331 A261005 A158872

Adjacent sequences:  A058106 A058107 A058108 * A058110 A058111 A058112

KEYWORD

nonn,hard

AUTHOR

Christian G. Bower, Nov 09 2000

EXTENSIONS

Updated Feb 19 2001

STATUS

approved

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Last modified October 23 19:26 EDT 2018. Contains 316530 sequences. (Running on oeis4.)