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A034826 Number of n-node rooted trees of height at most 9. 2
1, 1, 1, 2, 4, 9, 20, 48, 115, 286, 719, 1841, 4755, 12410, 32558, 85849, 226980, 601373, 1594870, 4232100, 11230771, 29798539, 79034638, 209526631, 555172356, 1470195001, 3891131705, 10292857772, 27212082536, 71905725130, 189911518888 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

N. J. A. Sloane, Table of n, a(n) for n=0..200

N. J. A. Sloane, Transforms

Index entries for sequences related to rooted trees

FORMULA

Take Euler transform of A034825 and shift right. (Christian G. Bower).

MAPLE

For Maple program see link in A000235.

with(numtheory): etr:= proc(p) local b; b:=proc(n) option remember; local d, j; if n=0 then 1 else add(add(d*p(d), d=divisors(j)) *b(n-j), j=1..n)/n fi end end: shr:= proc(p) n->`if`(n=0, 1, p(n-1)) end: b[0]:= etr(n->1): for j from 1 to 7 do b[j]:= etr(shr(b[j-1])) od: a:= shr(b[7]): seq(a(n), n=0..40); # Alois P. Heinz, Sep 08 2008

MATHEMATICA

etr[p_] := Module[{b}, b[n_] := b[n] = If[n == 0, 1, Sum[Sum[d*p[d], {d, Divisors[j]}]*b[n-j], {j, 1, n}]/n]; b]; shr[p_] = If[# == 0, 1, p[#-1]]&; b[0] = etr[1&]; For[j = 1, j <= 7, j++, b[j] = etr[shr[b[j-1]]]]; a = shr[b[7]]; Table[a[n], {n, 0, 31}] (* Jean-Fran├žois Alcover, Mar 10 2014, after Alois P. Heinz *)

CROSSREFS

See A001383 for details.

Sequence in context: A318855 A255639 A216062 * A145547 A292554 A318803

Adjacent sequences:  A034823 A034824 A034825 * A034827 A034828 A034829

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified January 17 22:48 EST 2019. Contains 319251 sequences. (Running on oeis4.)