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A292212 Number of (unlabeled) rooted trees with n leaf nodes and without unary nodes or outdegrees larger than six. 2
0, 1, 1, 2, 5, 12, 33, 89, 258, 756, 2279, 6957, 21592, 67689, 214451, 684850, 2203384, 7133042, 23222003, 75971636, 249646198, 823597534, 2726859943, 9057797752, 30176758016, 100810029178, 337614951216, 1133292965615, 3812333876764, 12849946139206 (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, 6)))

    end:

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

CROSSREFS

Column k=6 of A292085.

Sequence in context: A084075 A209717 A000560 * A212823 A292213 A032124

Adjacent sequences:  A292209 A292210 A292211 * A292213 A292214 A292215

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Sep 11 2017

STATUS

approved

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Last modified October 13 18:57 EDT 2019. Contains 327981 sequences. (Running on oeis4.)