cp's OEIS Frontend

A139624 Table read by rows: T(n,k) is the number of connected directed multigraphs with loops and no vertex of degree 0, with n arcs and k vertices, which are transitive (the existence of a path between two points implies the existence of an arc between those two points).

%I A139624 #13 Feb 07 2023 08:15:20
%S A139624 1,1,1,3,2,1,6,7,3,1,11
%N A139624 Table read by rows: T(n,k) is the number of connected directed multigraphs with loops and no vertex of degree 0, with n arcs and k vertices, which are transitive (the existence of a path between two points implies the existence of an arc between those two points).
%C A139624 Length of the n-th row: n+1.
%C A139624 T(n,1) = 1
%C A139624 Row sums: A139629.
%e A139624 Triangle begins
%e A139624 1;
%e A139624 1, 1;
%e A139624 3, 2, 1;
%e A139624 6, 7, 3, 1;
%Y A139624 Cf. A139623, A139625.
%K A139624 nonn,tabl,more
%O A139624 1,4
%A A139624 _Benoit Jubin_, May 01 2008