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A339646
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Number of inequivalent leaf colorings of series-reduced planted trees with n leaves using at most 2 colors.
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1
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1, 2, 5, 22, 85, 402, 1885, 9453, 48090, 251476, 1333517, 7177585, 39048327, 214523186, 1188037961, 6626311639, 37186187183, 209826251622, 1189699762371, 6774803376279, 38730124684829, 222194778028278, 1278828889503773, 7381829822338301, 42725078403203912
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OFFSET
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1,2
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COMMENTS
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Equivalence is up to permutation of the colors.
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LINKS
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FORMULA
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EXAMPLE
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a(1) = 1: 1.
a(2) = 2: (11), (12).
a(3) = 5: (111), (112), (1(11)), (1(12)), (1(22)).
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PROG
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(PARI) \\ See A339645 for cycleIndexSeries and InequivalentColoringsSeq.
InequivalentColoringsSeq(cycleIndexSeries(20), 2)
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CROSSREFS
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The case that colors may not be interchanged is A050381.
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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