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Search: id:A000683
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| A000683 |
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Number of 2-colored labeled graphs on n nodes.
(Formerly M4238 N1770)
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+0
11
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| 0, 1, 6, 40, 360, 4576, 82656, 2122240, 77366400, 4002843136, 293717546496, 30558458490880, 4505780560619520, 941417163728674816, 278628902101315608576, 116805328001281573519360
(list; graph; listen)
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OFFSET
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1,3
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REFERENCES
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F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 18, table 1.5.1, column 2 (divided by 2).
R. C. Read, The number of k-colored graphs on labeled nodes, Canad. J. Math., 12 (1960), 410-414.
R. C. Read, personal communication.
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..50
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FORMULA
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Reference gives generating function.
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CROSSREFS
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a(n)=(A047863(n)-2)/4. A diagonal of A058843.
Sequence in context: A083805 A006387 A014481 this_sequence A084270 A053677 A001367
Adjacent sequences: A000680 A000681 A000682 this_sequence A000684 A000685 A000686
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KEYWORD
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nonn,nice,easy
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AUTHOR
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njas
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EXTENSIONS
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More terms from Vladeta Jovovic (vladeta(AT)Eunet.yu), Feb 02 2000
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