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).
LINKS
FORMULA
E.g.f.: B(4*x)/2 where B(x) is e.g.f. of A000169.
a(n) = A052764(n)*2.
a(n) = 2^(2*n-1) * n^(n-1). - Vaclav Kotesovec, Mar 29 2014
MATHEMATICA
Table[2^(2*n-1)*n^(n-1), {n, 1, 20}] (* Vaclav Kotesovec, Mar 29 2014 *)
PROG
(Magma) [2^(2*n-1)*n^(n-1): n in [1..20]]; // Vincenzo Librandi, Mar 29 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Christian G. Bower, Jan 21 2008
EXTENSIONS
More terms from Vincenzo Librandi, Mar 29 2014
STATUS
approved