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A058105 Number of commutative asymmetric semigroups of order n. 4
1, 1, 3, 9, 39, 201, 1258, 10013 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..7.

Index entries for sequences related to semigroups

CROSSREFS

Cf. A001426. a(n) = A079201(n, A027423(n)).

Sequence in context: A130905 A030799 A273396 * A090012 A079096 A143293

Adjacent sequences:  A058102 A058103 A058104 * A058106 A058107 A058108

KEYWORD

nonn,hard

AUTHOR

Christian G. Bower, Nov 09 2000

EXTENSIONS

Updated Feb 19 2001. a(8) corrected Dec 26 2006

STATUS

approved

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Last modified February 17 16:26 EST 2018. Contains 299296 sequences. (Running on oeis4.)