A058108 Triangle read by rows: number of nonisomorphic semigroups of order n with k idempotents.
1, 2, 3, 5, 9, 10, 20, 50, 72, 46, 171, 309, 590, 594, 251, 5284, 2806, 5422, 7772, 5668, 1682, 1224331, 58583, 61323, 101539, 109107, 59576, 13213, 3667785000, 9207430, 1150085, 1466691, 1983558, 1626956, 690871, 119826, 105952488687468, 25412267163, 136799017, 27690828, 36991211, 39865274, 25666762, 8739857, 1228712
Offset: 1
Examples
Triangle begins:
1;
2, 3;
5, 9, 10;
20, 50, 72, 46;
171, 309, 590, 594, 251;
...
Links
- Andreas Distler, Classification and Enumeration of Finite Semigroups, A Thesis Submitted for the Degree of PhD, University of St Andrews (2010).
- 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
Extensions
Updated Feb 19 2001
More terms from Andreas Distler, Jan 13 2011