A058104 Number of asymmetric semigroups of order n.

1, 1, 3, 15, 112, 1221, 19684, 1458882, 3667253972, 105923135799007

Offset: 0

Author

Christian G. Bower, Nov 09 2000

Keywords

• nonn
• hard

Links

• A. Distler and T. Kelsey, The semigroups of order 9 and their automorphism groups, arXiv preprint arXiv:1301.6023 [math.CO], 2013.
• Index entries for sequences related to semigroups

Crossrefs

Cf. A027851, A058113, A079175.

Formula

a(n) = A079175(n, A027423(n)).

Extensions

Updated Feb 19 2001

a(8)-a(9) added from the Distler-Kelsey reference by Andrew Howroyd, Jan 26 2022