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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).
4
1, 1, 1, 4, 3, 1, 1, 7, 12, 9, 3, 1, 1, 13
OFFSET
1,4
COMMENTS
Length of the n^th row: 2n.
T(n,1) = T(n,2n) = 1 and T(n,2n-1) = 3 if n>1.
Row sums: A139628.
EXAMPLE
Triangle begins
1, 1;
1, 4, 3, 1;
1, 7, 12, 9, 3, 1;
CROSSREFS
KEYWORD
nonn,tabf,more
AUTHOR
Benoit Jubin, May 01 2008
STATUS
approved