A049414 Number of quasi-initially connected digraphs with n labeled nodes.

1, 3, 54, 3804, 1022320, 1065957628, 4389587378792, 72020744942708040, 4721708591209396542528, 1237892622263984613044109216, 1298060581376190776821670648395840

Offset: 1

Author

Vladeta Jovovic, Goran Kilibarda

Keywords

• nonn

Comments

We say that a node v of a digraph is a quasi-source iff for every other node u there exists directed path from u to v or from v to u. A digraph with at least one quasi-source is called quasi-initially connected.

Links

• Sean A. Irvine, Java program (github)
• V. Jovovic and G. Kilibarda, Enumeration of labeled quasi-initially connected digraphs, Discrete Math., 224 (2000), 151-163.

Crossrefs

Cf. A003027, A003028, A003029, A003030.

Row sums of A057272.

Formula

The recurrence formulas are too long to be presented here.