OFFSET
0,4
REFERENCES
F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Camb. 1998, p. 239, Eq 79, A_5.
LINKS
R. C. Richards, Shape distribution of height-balanced trees, Info. Proc. Lett., 17 (1983), 17-20.
FORMULA
a(n) = Sum_{h=0..5} A143897(h,n). - Alois P. Heinz, Mar 17 2013
MAPLE
a:= proc(n) local B, z; B:= proc(x, y, d) if d>=1 then x+B(x^2+2*x*y, x, d-1) else x fi end; coeff(B(z, 0, 5), z, n) end: seq(a(n), n=0..32); # Alois P. Heinz, Aug 27 2008
MATHEMATICA
a[n_] := Module[{B, z}, B[x_, y_, d_] := If[d >= 1, x+B[x^2+2*x*y, x, d-1], x]; Coefficient[B[z, 0, 5], z, n]]; Table[a[n], {n, 0, 32}] (* Jean-François Alcover, Feb 24 2015, after Alois P. Heinz *)
CROSSREFS
KEYWORD
nonn,fini,full
AUTHOR
STATUS
approved