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A066319
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A labeled structure simultaneously a tree and a cycle.
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0
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1, 1, 6, 96, 3000, 155520, 12101040, 1321205760, 192849310080, 36288000000000, 8556520581100800, 2471543044256563200, 858447696200353459200, 353034171594345598156800, 169665960401437500000000000
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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REFERENCES
| F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, pg 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.
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LINKS
| Index entries for sequences related to trees
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FORMULA
| a(n)=n^(max(0, n-3))*n!.
a(n)=mul(k*(n+1), k=2..n), n>=0. - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jan 29 2008
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MAPLE
| for n from 0 to 14 do printf(`%d, `, mul(k*(n+1), k=2..n)) od: - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jan 29 2008
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CROSSREFS
| Sequence in context: A156460 A038094 A126151 * A186269 A111826 A064753
Adjacent sequences: A066316 A066317 A066318 * A066320 A066321 A066322
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KEYWORD
| nonn
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AUTHOR
| Christian G. Bower (bowerc(AT)usa.net), Dec 13 2001
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EXTENSIONS
| Knuth reference from David Callan (callan(AT)stat.wisc.edu), Feb 07 2004
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