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A066319 A labeled structure simultaneously a tree and a cycle. 0
1, 1, 6, 96, 3000, 155520, 12101040, 1321205760, 192849310080, 36288000000000, 8556520581100800, 2471543044256563200, 858447696200353459200, 353034171594345598156800, 169665960401437500000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

REFERENCES

F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, p. 68 (2.1.37).

D. E. Knuth, A recurrence related to trees, Proc. Amer. Math. Soc. 105 (1989), 335-349. Reprinted as Chapter 39 of Selected Papers on Discrete Mathematics by D. E. Knuth.

LINKS

Table of n, a(n) for n=1..15.

Thorsten Weist, On the Euler characteristic of Kronecker moduli spaces, arXiv preprint arXiv:1203.2740, 2012.

Index entries for sequences related to trees

FORMULA

a(n) = n^(max(0, n-3))*n!.

a(n) = prod(k*(n+1), k=2..n), n>=0. - Zerinvary Lajos, Jan 29 2008

MAPLE

for n from 0 to 14 do printf(`%d, `, mul(k*(n+1), k=2..n)) od: # Zerinvary Lajos, Jan 29 2008

MATHEMATICA

nn=15; f[x_]:=Sum[n^(n-3)x^n, {n, 1, nn}]; Drop[ Range[0, nn]! CoefficientList[ Series[f[x], {x, 0, nn}], x], 1] (* Geoffrey Critzer, Sep 01 2013 *)

CROSSREFS

Sequence in context: A304646 A251576 A126151 * A186269 A111826 A213797

Adjacent sequences:  A066316 A066317 A066318 * A066320 A066321 A066322

KEYWORD

nonn

AUTHOR

Christian G. Bower, Dec 13 2001

EXTENSIONS

Knuth reference from David Callan, Feb 07 2004

STATUS

approved

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Last modified January 16 15:53 EST 2019. Contains 319195 sequences. (Running on oeis4.)