login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A036373 Number of ternary rooted trees with n nodes and height at most 5. 1
1, 1, 1, 2, 4, 8, 16, 33, 63, 121, 225, 415, 749, 1344, 2365, 4129, 7106, 12104, 20354, 33883, 55706, 90628, 145729, 231801, 364555, 567206, 872727, 1328545, 2000536, 2980554, 4393287, 6407683, 9246830, 13204526, 18657905, 26088244 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..35.

Index entries for sequences related to rooted trees

FORMULA

If T_i(z) = g.f. for ternary trees of height at most i, T_{i+1}(z)=1+z*(T_i(z)^3/6+T_i(z^2)*T_i(z)/2+T_i(z^3)/3); T_0(z) = 1.

MATHEMATICA

T[0] = {1}; T[n_] := T[n] = Module[{f, g}, f[z_] := Sum[T[n - 1][[i]]*z^(i - 1), {i, 1, Length[T[n - 1]]}]; g = 1 + z*(f[z]^3/6 + f[z^2]*f[z]/2 + f[z^3]/3); CoefficientList[g, z]]; A036373 = T[5] (* Jean-Fran├žois Alcover, Jan 19 2016, after Alois P. Heinz (A036370) *)

CROSSREFS

Cf. A036370.

Sequence in context: A233424 A137181 A272698 * A119610 A121485 A324406

Adjacent sequences:  A036370 A036371 A036372 * A036374 A036375 A036376

KEYWORD

nonn,fini

AUTHOR

N. J. A. Sloane, E. M. Rains (rains(AT)caltech.edu)

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 25 04:50 EDT 2019. Contains 323539 sequences. (Running on oeis4.)