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A054941
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Number of connected oriented graphs on n nodes.
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3
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1, 2, 20, 624, 55248, 13982208, 10358360640, 22792648882176, 149888345786341632, 2952810709943411146752, 174416705255313941476193280, 30901060796613886817249881227264
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| V. A. Liskovets, Some easily derivable sequences, J. Integer Sequences, 3 (2000), #00.2.2.
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FORMULA
| E.g.f.: 1+ln( Sum_{n >= 0} 3^binomial(n, 2)*x^n/n! ). - Vladeta Jovovic (vladeta(AT)eunet.rs), Feb 14 2003
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CROSSREFS
| Sequence in context: A197743 A009182 A015207 * A012495 A168480 A198761
Adjacent sequences: A054938 A054939 A054940 * A054942 A054943 A054944
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), May 24 2000
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EXTENSIONS
| More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Feb 14 2003
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