A038018 Triangle: T(n,k), k<=n: groupoids with n elements and k idempotents.

1, 0, 1, 3, 4, 3, 978, 1485, 729, 138, 56630832, 75503872, 37755904, 8390656, 700688, 813802235250650, 1017252851596875

Offset: 0

Author

Christian G. Bower, May 15 1998

Keywords

• nonn
• tabl
• more

Examples

			Triangle begins:
         1;
         0,        1;
         3,        4,        3;
       978,     1485,      729,     138;
  56630832, 75503872, 37755904, 8390656, 700688;
  ...
		

Links

• Index entries for sequences related to groupoids

Crossrefs

Row sums are A001329.

Main diagonal is A030247.

Columns k=0..1 are A030250, A030253.