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Search: id:A097174
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| A097174 |
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Total number of red nodes among tricolored labeled trees on n nodes. |
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+0
5
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| 1, 0, 6, 12, 320, 2190, 51492, 685496, 17286768, 348213690, 9956411300, 266065478052, 8737396913544, 287741445880070, 10816320294520860, 420123621828718320, 17913098835916877792, 798053882730994171890
(list; graph; listen)
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OFFSET
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1,3
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LINKS
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S. Coulomb and M. Bauer, On vertex covers, matchings and random trees
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FORMULA
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E.g.f.: A(x) = -T(-T(x)), with T(x)=Sum[k=1..inf, A000169(k)/k!*x^k].
a(n) = -n^(n-1) * Sum[l=1..n, (-l/n)^l*C(n, l)].
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CROSSREFS
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Cf. A097170, A097171, A097172, A097173, A000272.
Sequence in context: A014402 A051784 A158046 this_sequence A032511 A036900 A159282
Adjacent sequences: A097171 A097172 A097173 this_sequence A097175 A097176 A097177
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KEYWORD
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nonn
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AUTHOR
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Ralf Stephan, Jul 30 2004
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