A101488 Number of naturally embedded binary trees with n nodes that have no label greater than 0.

1, 1, 1, 2, 4, 10, 26, 73, 213, 645, 2007, 6391, 20741, 68407, 228753, 774162, 2647548, 9138342, 31802118, 111489492, 393442848, 1396771812, 4985732628, 17884908282, 64449398994, 233220788850, 847211744806, 3088649627798

Offset

0,4

Links

Table of n, a(n) for n=0..27.

M. Bousquet-Mélou, Limit laws for embedded trees, arXiv:math/0501266 [math.CO], 2005.

Formula

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

Mathematica

CoefficientList[((1-4z)^(3/2)-1+8z-2z^2)/(2z(1+z)) + O[z]^28, z] (* Jean-François Alcover, Jul 25 2018 *)

Crossrefs

First row of array A101489.

Sequence in context: A148098 A210043 A049130 * A279544 A245898 A230662

Adjacent sequences: A101485 A101486 A101487 * A101489 A101490 A101491

Keyword

nonn

Author

Ralf Stephan, Jan 21 2005

Status

approved