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%I #11 Feb 02 2020 17:41:42
%S 2,8,96,2048,64000,2654208,137682944,8589934592,626913312768,
%T 52428800000000,4944974716076032,519400496868360192,
%U 60134924074807721984,7609328110443312447488,1044855521280000000000000,154742504910672534362390528,24588026787102364507838611456
%N Number of labeled marked trees with n nodes.
%C A marked tree is a 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 Andrew Howroyd, <a href="/A136797/b136797.txt">Table of n, a(n) for n = 1..200</a>
%H <a href="/index/Tra#trees">Index entries for sequences related to trees</a>
%F a(n) = A136796(n)/n.
%F a(n) = 2^(2*n-1) * n^(n-2). - _Andrew Howroyd_, Feb 02 2020
%o (PARI) a(n) = {2^(2*n-1) * n^(n-2)} \\ _Andrew Howroyd_, Feb 02 2020
%Y Cf. A136796.
%K nonn
%O 1,1
%A _Christian G. Bower_, Jan 21 2008
%E Terms a(15) and beyond from _Andrew Howroyd_, Feb 02 2020
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