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Search: id:A060516
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| A060516 |
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Number of series-reduced (or homeomorphically irreducible) graphs with loops on n labeled nodes. |
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13
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| 1, 1, 5, 26, 328, 9700, 711836, 111817032, 35130791054, 21495893690664, 25409892375220474, 58052821046020873856, 257486314335782707924088, 2230295461268044025586193298, 37948847404292424846290915818844
(list; graph; listen)
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OFFSET
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0,3
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REFERENCES
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I. P. Goulden and D. M. Jackson, Combinatorial Enumeration, John Wiley and Sons, N.Y., 1983.
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FORMULA
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E.g.f. : (1 + x)^( - 1/2) * exp( - x/2 - x^2/4) * Sum_{k=0..inf} 2^binomial(k + 1, 2) * exp( - x * k^2/(2 * (1 + x)) + x * k/2) * x^k/k!.
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CROSSREFS
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Cf. A003514. Row sums of A060517.
Adjacent sequences: A060513 A060514 A060515 this_sequence A060517 A060518 A060519
Sequence in context: A041042 A048690 A106296 this_sequence A077537 A090644 A015490
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KEYWORD
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easy,nonn
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AUTHOR
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Vladeta Jovovic (vladeta(AT)Eunet.yu), Mar 24 2001
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