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A292210 Number of (unlabeled) rooted trees with n leaf nodes and without unary nodes or outdegrees larger than four. 2
0, 1, 1, 2, 5, 11, 30, 80, 228, 656, 1945, 5835, 17808, 54881, 170951, 536726, 1697774, 5403629, 17295686, 55630538, 179726346, 582942079, 1897565974, 6196973039, 20297954197, 66666192488, 219505550167, 724415274090, 2395838962114, 7939424272536 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

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

Index entries for sequences related to rooted trees

MAPLE

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

      `if`(v=0, 1, 0), `if`(i<1 or v<1 or n<v, 0,

      `if`(v=n, 1, add(binomial(a(i)+j-1, j)*

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

    end:

a:= proc(n) option remember; `if`(n<2, n,

      add(b(n, n+1-j, j), j=2..min(n, 4)))

    end:

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

CROSSREFS

Column k=4 of A292085.

Sequence in context: A121134 A144959 A131347 * A079225 A139466 A291139

Adjacent sequences:  A292207 A292208 A292209 * A292211 A292212 A292213

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Sep 11 2017

STATUS

approved

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Last modified March 20 19:23 EDT 2019. Contains 321349 sequences. (Running on oeis4.)