

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
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OFFSET

1,4


COMMENTS

Length of the n^th row: 2n.
T(n,1) = T(n,2n) = 1 and T(n,2n1) = 3 if n>1.
Row sums: A139628.


LINKS

Table of n, a(n) for n=1..14.


EXAMPLE

Triangle begins
1, 1;
1, 4, 3, 1;
1, 7, 12, 9, 3, 1;


CROSSREFS

Cf. A136564, A139624, A139625.
Sequence in context: A157464 A046546 A189967 * A278072 A216482 A080758
Adjacent sequences: A139620 A139621 A139622 * A139624 A139625 A139626


KEYWORD

nonn,tabf,more


AUTHOR

Benoit Jubin, May 01 2008


STATUS

approved



