A038056 Number of trees with n 2-colored nodes.

2, 3, 6, 18, 54, 189, 700, 2778, 11486, 49377, 217936, 984818, 4533004, 21198962, 100471862, 481754806, 2333465628, 11404047817, 56177574628, 278710061814, 1391617108600, 6988781174376, 35283390923324, 178990052273558, 912019786448570, 4665994686718118

Offset

1,1

Links

Alois P. Heinz, Table of n, a(n) for n = 1..1000

Index entries for sequences related to trees

Formula

G.f.: B(x) - B^2(x)/2 + B(x^2)/2, where B(x) is g.f. for A038055.

Crossrefs

Cf. A000055, A038055-A038062. Row sums of A294783.

Sequence in context: A057581 A089424 A083563 * A072241 A093468 A185625

Adjacent sequences: A038053 A038054 A038055 * A038057 A038058 A038059

Keyword

nonn

Author

Christian G. Bower, Jan 04 1999

Status

approved