A244537 Number of ordered unlabeled rooted trees with n nodes such that the minimal outdegree of inner nodes equals 8.

1, 0, 0, 0, 0, 0, 0, 0, 8, 17, 18, 19, 20, 21, 22, 23, 116, 325, 676, 1080, 1540, 2059, 2640, 3286, 5240, 10241, 20604, 39305, 68286, 109705, 165946, 239629, 351898, 552311, 931070, 1633871, 2879668, 4951860, 8208631, 13094200, 20436400, 31939817, 50935060

Offset

9,9

Links

Alois P. Heinz, Table of n, a(n) for n = 9..1000

Maple

b:= proc(n, t, k) option remember; `if`(n=0,
      `if`(t in [0, k], 1, 0), `if`(t>n, 0, add(b(j-1, k$2)*
       b(n-j, max(0, t-1), k), j=1..n)))
    end:
a:= n-> b(n-1, 8$2) -b(n-1, 9$2):
seq(a(n), n=9..55);

Crossrefs

Column k=8 of A244530.

Cf. A244462.

Sequence in context: A234839 A066554 A302976 * A046459 A274770 A075485

Adjacent sequences: A244534 A244535 A244536 * A244538 A244539 A244540

Keyword

nonn

Author

Joerg Arndt and Alois P. Heinz, Jun 29 2014

Status

approved