A090603 Number of n-element labeled groupoids with a fixed identity.

1, 2, 81, 262144, 152587890625, 28430288029929701376, 2651730845859653471779023381601, 178405961588244985132285746181186892047843328, 11790184577738583171520872861412518665678211592275841109096961

Offset: 1

Author

Christian G. Bower, Dec 05 2003

Keywords

• nonn

Comments

Also labeled partial groupoids with n-1 elements.

Links

• Eric Weisstein's World of Mathematics, Groupoid.
• Index entries for sequences related to groupoids

Programs

Mathematica

Table[n^(n-1)^2,{n,10}] (* Harvey P. Dale, May 31 2019 *)

Formula

a(n) = n^((n-1)^2). - Alois P. Heinz, Jul 30 2012