|
| |
|
|
A097174
|
|
Total number of red nodes among tricolored labeled trees on n nodes.
|
|
4
| |
|
|
1, 0, 6, 12, 320, 2190, 51492, 685496, 17286768, 348213690, 9956411300, 266065478052, 8737396913544, 287741445880070, 10816320294520860, 420123621828718320, 17913098835916877792, 798053882730994171890
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,3
|
|
|
LINKS
| S. Coulomb and M. Bauer, On vertex covers, matchings and random trees
|
|
|
FORMULA
| 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)].
|
|
|
CROSSREFS
| Cf. A097170, A097171, A097172, A097173, A000272.
Sequence in context: A181493 A051784 A158046 * A191415 A032511 A036900
Adjacent sequences: A097171 A097172 A097173 * A097175 A097176 A097177
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Ralf Stephan, Jul 30 2004
|
| |
|
|
