A244536 Number of ordered unlabeled rooted trees with n nodes such that the minimal outdegree of inner nodes equals 7.

1, 0, 0, 0, 0, 0, 0, 7, 15, 16, 17, 18, 19, 20, 91, 253, 529, 852, 1225, 1651, 2133, 3493, 6931, 14095, 27156, 47648, 77297, 118031, 182462, 300441, 527398, 954712, 1722370, 3015910, 5074611, 8342271, 13730760, 23036563, 39558564, 68974240, 120541276

Offset

8,8

Links

Alois P. Heinz, Table of n, a(n) for n = 8..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, 7$2) -b(n-1, 8$2):
seq(a(n), n=8..50);

Crossrefs

Column k=7 of A244530.

Cf. A244461.

Sequence in context: A076401 A180114 A204740 * A237054 A216848 A065566

Adjacent sequences: A244533 A244534 A244535 * A244537 A244538 A244539

Keyword

nonn

Author

Joerg Arndt and Alois P. Heinz, Jun 29 2014

Status

approved