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A292213 Number of (unlabeled) rooted trees with n leaf nodes and without unary nodes or outdegrees larger than seven. 2
0, 1, 1, 2, 5, 12, 33, 90, 260, 763, 2302, 7035, 21854, 68581, 217485, 695229, 2238965, 7255380, 23643501, 77426852, 254678757, 841028918, 2787320206, 9267764857, 30906754731, 103350631437, 346465277423, 1164150100182, 3920004155435, 13225916804136 (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, 7)))

    end:

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

CROSSREFS

Column k=7 of A292085.

Sequence in context: A000560 A292212 A212823 * A032124 A292214 A292215

Adjacent sequences:  A292210 A292211 A292212 * A292214 A292215 A292216

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Sep 11 2017

STATUS

approved

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Last modified November 16 15:26 EST 2018. Contains 317274 sequences. (Running on oeis4.)