A038056 - OEIS

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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

(list; graph; refs; listen; history; text; internal format)

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