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A038060 Number of trees with 3-colored nodes. 1
1, 3, 6, 18, 75, 342, 1773, 9894, 58596, 362061, 2314119, 15185223, 101830986, 695253993, 4819762446, 33851833506, 240472935735, 1725315714729, 12487872432924, 91097741283408, 669227023979088, 4947500029023540 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..21.

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 A038059.

CROSSREFS

Cf. A000055, A038055-A038062.

Equals 3 * A006965(n).

Sequence in context: A102962 A076510 A220816 * A135504 A307334 A057268

Adjacent sequences:  A038057 A038058 A038059 * A038061 A038062 A038063

KEYWORD

nonn

AUTHOR

Christian G. Bower, Jan 04 1999

STATUS

approved

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Last modified November 19 22:34 EST 2019. Contains 329323 sequences. (Running on oeis4.)