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Search: id:A047994
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| A047994 |
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Unitary totient (or unitary phi) function uphi(n). |
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+0
22
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| 1, 1, 2, 3, 4, 2, 6, 7, 8, 4, 10, 6, 12, 6, 8, 15, 16, 8, 18, 12, 12, 10, 22, 14, 24, 12, 26, 18, 28, 8, 30, 31, 20, 16, 24, 24, 36, 18, 24, 28, 40, 12, 42, 30, 32, 22, 46, 30, 48, 24, 32, 36, 52, 26, 40, 42, 36, 28, 58, 24, 60, 30, 48, 63, 48, 20, 66, 48, 44, 24, 70
(list; graph; listen)
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OFFSET
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1,3
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REFERENCES
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M. Lal, Iterates of the unitary totient function, Math. Comp., 28 (1974), 301-302.
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..10000
S. R. Finch, Unitarism and infinitarism.
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FORMULA
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If n = Product p_i^e_i, uphi(n) = Product (p_i^e_i - 1).
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EXAMPLE
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a(12)=a(3)a(4)=2*3=6.
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MATHEMATICA
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uphi[n_] := (Times @@ (Table[ #[[1]]^ #[[2]] - 1, {1} ] & /@ FactorInteger[n]))[[1]]; Table[ uphi[n], {n, 2, 75}] (from Robert G. Wilson v Sep 06 2004)
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CROSSREFS
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Cf. A003271.
Sequence in context: A091732 A109746 A061020 this_sequence A117009 A103300 A141331
Adjacent sequences: A047991 A047992 A047993 this_sequence A047995 A047996 A047997
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KEYWORD
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nonn,easy,nice,mult
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AUTHOR
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njas
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EXTENSIONS
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More terms from Jud McCranie (j.mccranie(AT)comcast.net).
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