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Search: id:A052283
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| A052283 |
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Triangle read by rows giving numbers of directed graphs by numbers of nodes and arcs. |
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+0
3
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| 1, 1, 1, 1, 1, 1, 4, 4, 4, 1, 1, 1, 1, 5, 13, 27, 38, 48, 38, 27, 13, 5, 1, 1, 1, 1, 5, 16, 61, 154, 379, 707, 1155, 1490, 1670, 1490, 1155, 707, 379, 154, 61, 16, 5, 1, 1, 1, 1, 5, 17, 76, 288, 1043, 3242, 8951, 21209, 43863, 78814, 124115, 171024, 207362, 220922
(list; graph; listen)
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OFFSET
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1,7
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REFERENCES
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F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 247.
J. L. Gross and J. Yellen, eds., Handbook of Graph Theory, CRC Press, 2004; p. 522.
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LINKS
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Eric Weisstein's World of Mathematics, Simple Directed Graph
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EXAMPLE
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[1],[1,1,1],[1,1,4,4,4,1,1],[1,1,5,13,27,38,48,38,27,13,5,1,1]; (the last batch giving the numbers of directed graphs with 4 nodes and from 0 to 12 arcs).
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CROSSREFS
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Cf. A000273, A070166.
Sequence in context: A066602 A073816 A084452 this_sequence A133889 A117683 A109610
Adjacent sequences: A052280 A052281 A052282 this_sequence A052284 A052285 A052286
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KEYWORD
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nonn,tabf
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AUTHOR
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Vladeta Jovovic (vladeta(AT)Eunet.yu), Feb 07 2000
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