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A049414
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Number of quasi-initially connected digraphs with n labeled nodes.
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3
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1, 3, 54, 3804, 1022320, 1065957628, 4389587378792, 72020744942708040, 4721708591209396542528, 1237892622263984613044109216, 1298060581376190776821670648395840
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OFFSET
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1,2
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COMMENTS
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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.
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REFERENCES
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V. Jovovic and G. Kilibarda, Enumeration of labeled quasi-initially connected digraphs, Discrete Math., 224 (2000), 151-163.
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LINKS
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Table of n, a(n) for n=1..11.
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FORMULA
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The recurrence formulas are too long to be presented here.
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CROSSREFS
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Cf. A003027, A003028, A003029, A003030.
Sequence in context: A091796 A171213 A006025 * A003027 A054545 A158103
Adjacent sequences: A049411 A049412 A049413 * A049415 A049416 A049417
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KEYWORD
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nonn
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AUTHOR
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Vladeta Jovovic, Goran Kilibarda (vladeta(AT)eunet.rs)
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STATUS
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approved
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