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A049414 Number of quasi-initially connected digraphs with n labeled nodes. 3
1, 3, 54, 3804, 1022320, 1065957628, 4389587378792, 72020744942708040, 4721708591209396542528, 1237892622263984613044109216, 1298060581376190776821670648395840 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

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

Table of n, a(n) for n=1..11.

V. Jovovic and G. Kilibarda, Enumeration of labeled quasi-initially connected digraphs, Discrete Math., 224 (2000), 151-163.

FORMULA

The recurrence formulas are too long to be presented here.

CROSSREFS

Cf. A003027, A003028, A003029, A003030.

Row sums of A057272.

Sequence in context: A091796 A171213 A006025 * A003027 A054545 A158103

Adjacent sequences:  A049411 A049412 A049413 * A049415 A049416 A049417

KEYWORD

nonn

AUTHOR

Vladeta Jovovic, Goran Kilibarda

STATUS

approved

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Last modified August 6 11:55 EDT 2020. Contains 336246 sequences. (Running on oeis4.)