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A292553 Number of rooted unlabeled trees on n nodes where each node has at most 8 children. 11
1, 1, 1, 2, 4, 9, 20, 48, 115, 286, 718, 1839, 4757, 12460, 32897, 87592, 234746, 633013, 1715851, 4673320, 12781759, 35093010, 96681705, 267199518, 740580555, 2058042803, 5733101603, 16006590851, 44782679547, 125533577578, 352525803976, 991634575368 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..1000

Marko Riedel, Trees with bounded degree.

Marko Riedel, Maple code for sequences A001190, A000598, A036718, A036721, A036722, A182378, A292553, A292554, A292555, A292556 (FEQ 1).

Marko Riedel, Maple code for sequences A001190, A000598, A036718, A036721, A036722, A182378, A292553, A292554, A292555, A292556 (FEQ 2)

Marko Riedel, Maple code (FEQ 2) optimized for speed.

FORMULA

Functional equation of G.f. is T(z) = z + z*Sum_{q=1..8} Z(S_q)(T(z)) with Z(S_q) the cycle index of the symmetric group. Alternate FEQ is T(z) = 1 + z*Z(S_8)(T(z)).

a(n) = Sum_{j=1..8} A244372(n,j) for n>0, a(0) = 1. - Alois P. Heinz, Sep 20 2017

MAPLE

b:= proc(n, i, t, k) option remember; `if`(n=0, 1,

      `if`(i<1, 0, add(binomial(b((i-1)$2, k$2)+j-1, j)*

       b(n-i*j, i-1, t-j, k), j=0..min(t, n/i))))

    end:

a:= n-> `if`(n=0, 1, b(n-1$2, 8$2)):

seq(a(n), n=0..35);  # Alois P. Heinz, Sep 20 2017

CROSSREFS

Cf. A000081, A001190, A000598, A036718, A036721, A036722, A182378, A244372, A292554, A292555, A292556.

Column k=8 of A299038.

Sequence in context: A215971 A034825 A145546 * A255639 A216062 A034826

Adjacent sequences:  A292550 A292551 A292552 * A292554 A292555 A292556

KEYWORD

nonn

AUTHOR

Marko Riedel, Sep 18 2017

STATUS

approved

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Last modified April 19 07:05 EDT 2018. Contains 302673 sequences. (Running on oeis4.)