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Number of pointed (distinguished element) idempotent groupoids.
3

%I #15 Dec 19 2021 13:50:34

%S 1,4,378,2798336,3973658465625,1842282678468471349824,

%T 433296503176904197061300041939288,

%U 74235003800935257803650942510752495927455127552

%N Number of pointed (distinguished element) idempotent groupoids.

%H <a href="/index/Gre#groupoids">Index entries for sequences related to groupoids</a>

%F 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))).

%Y Cf. A001329, A030247.

%K nonn

%O 1,2

%A _Christian G. Bower_, May 15 1998