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A038080 Number of identity trees with 3-colored nodes. 3
1, 3, 3, 9, 39, 189, 981, 5490, 31674, 189954, 1170126, 7382745, 47494197, 310712808, 2061987642, 13855192866, 94113385437, 645424668666, 4464027720900, 31110200069511, 218292811705458, 1541172223659249 (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 A038079.

CROSSREFS

Cf. A000220. A038077-A038079.

Sequence in context: A241278 A100239 A245023 * A257621 A190960 A257623

Adjacent sequences:  A038077 A038078 A038079 * A038081 A038082 A038083

KEYWORD

nonn

AUTHOR

Christian G. Bower, Jan 04 1999

STATUS

approved

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Last modified May 31 02:51 EDT 2020. Contains 334747 sequences. (Running on oeis4.)