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Number of naturally embedded binary trees with n nodes that have no label greater than 0.
1

%I #13 Jul 25 2018 06:14:34

%S 1,1,1,2,4,10,26,73,213,645,2007,6391,20741,68407,228753,774162,

%T 2647548,9138342,31802118,111489492,393442848,1396771812,4985732628,

%U 17884908282,64449398994,233220788850,847211744806,3088649627798

%N Number of naturally embedded binary trees with n nodes that have no label greater than 0.

%H M. Bousquet-Mélou, <a href="https://arxiv.org/abs/math/0501266">Limit laws for embedded trees</a>, arXiv:math/0501266 [math.CO], 2005.

%F G.f.: ((1-4z)^(3/2)-1+8z-2z^2)/(2z(1+z)).

%t CoefficientList[((1-4z)^(3/2)-1+8z-2z^2)/(2z(1+z)) + O[z]^28, z] (* _Jean-François Alcover_, Jul 25 2018 *)

%Y First row of array A101489.

%K nonn

%O 0,4

%A _Ralf Stephan_, Jan 21 2005