A038015 Number of pointed (distinguished element) idempotent groupoids.

1, 4, 378, 2798336, 3973658465625, 1842282678468471349824, 433296503176904197061300041939288, 74235003800935257803650942510752495927455127552

Offset: 1

Author

Christian G. Bower, May 15 1998

Keywords

• nonn

Links

• Index entries for sequences related to groupoids

Crossrefs

Cf. A001329, A030247.

Formula

Here fixF[n] = n(1)*Product_{i, j >= 1}(Sum_{d|[i, j]}(d*n(d))^((i, j)*n(i)*n(j)-(i=j)n(i))).