id:A136719 - OEIS Search Results

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Number of labeled directed trees with n nodes.

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1

1, 3, 27, 432, 10125, 314928, 12252303, 573308928, 31381059609, 1968300000000, 139234453205859, 10968475320188928, 952427511967417317, 90388408459919044608, 9308590679915771484375 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`A directed tree is a tree where each edge is assigned one or both directions.`
	REFERENCES	`F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, pg 292 (4.1.58)`
	LINKS	`Index entries for sequences related to trees`
	FORMULA	`a(n) = A052756(n)/n.`
	CROSSREFS	`Cf. A006965 (unlabeled version).` `Sequence in context: A011781 A094577 A108525 this_sequence A111844 A118714 A089506` `Adjacent sequences: A136716 A136717 A136718 this_sequence A136720 A136721 A136722`
	KEYWORD	`nonn`
	AUTHOR	`Christian G. Bower (bowerc(AT)usa.net), Jan 18 2008`

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.

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