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A318851 Number of rooted trees with n nodes such that no more than four isomorphic subtrees extend from the same node. 2
0, 1, 1, 2, 4, 9, 19, 46, 110, 273, 684, 1746, 4503, 11758, 30943, 82118, 219341, 589485, 1592447, 4322433, 11781565, 32235688, 88503331, 243750729, 673246211, 1864422803, 5175655984, 14399854855, 40146793094, 112145140408, 313826549732, 879685174894 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..2143

MAPLE

h:= proc(n, m, t) option remember; `if`(m=0, binomial(n+t, t),

      `if`(n=0, 0, add(h(n-1, m-j, t+1), j=1..min(4, m))))

    end:

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

      add(b(n-i*j, i-1)*h(a(i), j, 0), j=0..n/i)))

    end:

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

seq(a(n), n=0..35);

CROSSREFS

Column k=4 of A318757.

Sequence in context: A036718 A134964 A318798 * A052328 A133228 A036717

Adjacent sequences:  A318848 A318849 A318850 * A318852 A318853 A318854

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Sep 04 2018

STATUS

approved

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Last modified May 10 01:36 EDT 2021. Contains 343747 sequences. (Running on oeis4.)