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Number of groupoids (categories all of whose morphisms are invertible) with n morphisms.
2

%I #2 Mar 31 2012 10:31:22

%S 1,1,2,3,7,9,16,22,42,57,90,124,204,275,413,562,866,1161,1685,2264,

%T 3308,4407

%N Number of groupoids (categories all of whose morphisms are invertible) with n morphisms.

%C Row sums of A140188 (see comments and formula there).

%Y Cf. A140185, A140188.

%K nonn

%O 0,3

%A _Benoit Jubin_, May 12 2008