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A marked tree is a tree where each node and edge is marked as + or -.
F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, p. 293 (4.1.60).
Table of n, a(n) for n=1..14.
Index entries for sequences related to trees
a(n) = A136796(n)/n.
Sequence in context: A098272 A087540 A052713 * A255132 A297332 A009752
Adjacent sequences: A136794 A136795 A136796 * A136798 A136799 A136800
Christian G. Bower, Jan 21 2008