A058168 Triangle: Number of asymmetric commutative semigroups of order n with k idempotents.

1, 2, 1, 3, 5, 1, 7, 18, 12, 2, 24, 65, 73, 34, 5, 133, 276, 399, 309, 123, 18, 1722, 1595, 2240, 2331, 1500, 544, 81

Offset: 1

Author

Christian G. Bower, Nov 19 2000

Keywords

• nonn
• tabl
• hard

Examples

			1; 2,1; 3,5,1; 7,18,12,2; 24,65,73,34,5; ...
		

Links

• Index entries for sequences related to semigroups

Crossrefs

Row sums give A058105.