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A124329 Number of ordered trees with n edges, with thinning limbs and with root of degree 2. An ordered tree with thinning limbs is such that if a node has k children, all its children have at most k children. 1
0, 1, 2, 5, 10, 22, 46, 101, 220, 492, 1104, 2515, 5762, 13327, 30994, 72555, 170654, 403350, 957134, 2279947, 5449012, 13063595, 31406516, 75701507, 182902336, 442885682, 1074604288, 2612341855, 6361782006, 15518343596, 37912613630 (list; graph; refs; listen; history; internal format)
OFFSET

1,3

COMMENTS

Column 2 of A124328.

FORMULA

G.f.=[1-z-2z^2-sqrt(1-2z-3z^2+4z^3)]/[2(1-z)z^2].

MAPLE

G:=(1-z-2*z^2-sqrt(1-2*z-3*z^2+4*z^3))/2/z^2/(1-z): Gser:=series(G, z=0, 40): seq(coeff(Gser, z, n), n=1..36);

CROSSREFS

Cf. A124344, A124328.

Sequence in context: A026655 A100938 A018004 * A144520 A101399 A018109

Adjacent sequences:  A124326 A124327 A124328 * A124330 A124331 A124332

KEYWORD

nonn

AUTHOR

Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 03 2006

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Last modified February 14 19:37 EST 2012. Contains 205663 sequences.