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A038078 Number of identity trees with 2-colored nodes. 1
1, 2, 1, 2, 6, 20, 69, 270, 1026, 4120, 16794, 70230, 298306, 1288912, 5642559, 25007756, 111998920, 506348902, 2308338456, 10602357346, 49026021552, 228085486580, 1067020210339, 5016982766202, 23698640081356 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..24.

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 A038077.

CROSSREFS

Cf. A000220. A038077-A038080.

Sequence in context: A170829 A032085 A032163 * A000139 A114572 A052621

Adjacent sequences:  A038075 A038076 A038077 * A038079 A038080 A038081

KEYWORD

nonn

AUTHOR

Christian G. Bower, Jan 04 1999.

STATUS

approved

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Last modified May 23 09:11 EDT 2013. Contains 225586 sequences.