%I A139623
%S A139623 1,1,1,4,3,1,1,7,12,9,3,1,1,13
%N A139623 Table read by rows: T(n,k) is the number of 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 A139623 Length of the n^th row: 2n.
%C A139623 T(n,1) = T(n,2n) = 1 and T(n,2n-1) = 3 if n>1.
%C A139623 Row sums: A139628.
%H A139623 B. Jubin, <a href="http://math.berkeley.edu/~jubin/oeis.html">Sequences 
               contributed to the OEIS</a>
%Y A139623 Cf. A136564, A139624, A139625.
%Y A139623 Sequence in context: A016500 A157464 A046546 this_sequence A080758 A123683 
               A010306
%Y A139623 Adjacent sequences: A139620 A139621 A139622 this_sequence A139624 A139625 
               A139626
%K A139623 nonn
%O A139623 1,4
%A A139623 Benoit Jubin (benoit_jubin(AT)yahoo.fr), May 01 2008