A229395 Number of shapes of balanced 10-ary trees with n nodes, where a tree is balanced if the total number of nodes in subtrees corresponding to the branches of any node differ by at most one.

1, 1, 10, 45, 120, 210, 252, 210, 120, 45, 10, 1, 100, 4500, 120000, 2100000, 25200000, 210000000, 1200000000, 4500000000, 10000000000, 10000000000, 450000000000, 9112500000000, 109350000000000, 861131250000000, 4650108750000000, 17437907812500000

Offset

0,3

Comments

a(n) = 1 for n in { A002275 }.

Links

Alois P. Heinz, Table of n, a(n) for n = 0..1111

Maple

a:= proc(n) option remember; local m, r; if n<2 then 1 else
      r:= iquo(n-1, 10, 'm'); binomial(10, m) *a(r+1)^m *a(r)^(10-m) fi
    end:
seq(a(n), n=0..111);

Crossrefs

Column k=10 of A221857.

Sequence in context: A001488 A009540 A010926 * A306965 A045852 A226450

Adjacent sequences: A229392 A229393 A229394 * A229396 A229397 A229398

Keyword

nonn,look

Author

Alois P. Heinz, Sep 21 2013

Status

approved