A136794 - OEIS

%I #9 Dec 13 2018 11:32:04

%S 2,8,52,376,2998,25256,222128,2013680,18691522,176743160,1696546848,

%T 16488151400,161919802562,1604274741608,16016845623764,

%U 160977882238968,1627406260427490,16537733701226936

%N Number of unlabeled marked rooted trees with n nodes.

%C A marked rooted tree is a rooted tree where each node and edge is marked as + or -.

%D F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, p. 293 (4.1.60).

%H L. Foissy, <a href="https://arxiv.org/abs/1811.07572">Algebraic structures on typed decorated rooted trees</a>, arXiv:1811.07572 (2018)

%H <a href="/index/Ro#rooted">Index entries for sequences related to rooted trees</a>

%F a(n) = A136793(n)/2 = A052763(n)*2.

%Y Cf. A136795 (tree version), A136796 (labeled version).

%K nonn

%O 1,1

%A _Christian G. Bower_, Jan 21 2008