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A136794
Number of unlabeled marked rooted trees with n nodes.
3
2, 8, 52, 376, 2998, 25256, 222128, 2013680, 18691522, 176743160, 1696546848, 16488151400, 161919802562, 1604274741608, 16016845623764, 160977882238968, 1627406260427490, 16537733701226936
OFFSET
1,1
COMMENTS
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, p. 293 (4.1.60).
FORMULA
a(n) = A136793(n)/2 = A052763(n)*2.
CROSSREFS
Cf. A136795 (tree version), A136796 (labeled version).
Sequence in context: A030518 A123188 A027329 * A125787 A358031 A368453
KEYWORD
nonn
AUTHOR
Christian G. Bower, Jan 21 2008
STATUS
approved