id:A136794 - OEIS Search Results

Search: id:A136794

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Number of unlabeled marked rooted trees with n nodes.

+0
4

2, 8, 52, 376, 2998, 25256, 222128, 2013680, 18691522, 176743160, 1696546848, 16488151400, 161919802562, 1604274741608, 16016845623764, 160977882238968, 1627406260427490, 16537733701226936 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`A marked rooted tree is a rooted tree where each node and edge is marked as + or -.`
	REFERENCES	`F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, pg 293 (4.1.60)`
	LINKS	`Index entries for sequences related to rooted trees`
	FORMULA	`a(n) = A136793(n)/2 = A052763(n)*2.`
	CROSSREFS	`Cf. A136795 (tree version), A136796 (labeled version).` `Sequence in context: A030518 A123188 A027329 this_sequence A125787 A007832 A111088` `Adjacent sequences: A136791 A136792 A136793 this_sequence A136795 A136796 A136797`
	KEYWORD	`nonn`
	AUTHOR	`Christian G. Bower (bowerc(AT)usa.net), Jan 21 2008`

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Last modified March 20 09:10 EDT 2010. Contains 173642 sequences.

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