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Search: id:A062821
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| A062821 |
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Number of divisors of totient of n. |
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+0
6
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| 1, 1, 2, 2, 3, 2, 4, 3, 4, 3, 4, 3, 6, 4, 4, 4, 5, 4, 6, 4, 6, 4, 4, 4, 6, 6, 6, 6, 6, 4, 8, 5, 6, 5, 8, 6, 9, 6, 8, 5, 8, 6, 8, 6, 8, 4, 4, 5, 8, 6, 6, 8, 6, 6, 8, 8, 9, 6, 4, 5, 12, 8, 9, 6, 10, 6, 8, 6, 6, 8, 8, 8, 12, 9, 8, 9, 12, 8, 8, 6, 8, 8, 4, 8, 7, 8, 8, 8, 8, 8, 12, 6, 12, 4, 12, 6, 12, 8, 12, 8
(list; graph; listen)
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OFFSET
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1,3
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,2000
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FORMULA
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DivisorSigma[0, EulerPhi[n]], i.e. A000005[A000010(n)]
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EXAMPLE
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Number of divisors of Phi[n] can be larger [n=11: d[11]=2 < d[10]=4], equal[n=28: d[28]=6 = d[12]=6 ] or smaller [n=10: d[10]=4 > d[4]=3] than that of n.
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PROGRAM
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(PARI) { for (n=1, 2000, write("b062821.txt", n, " ", numdiv(eulerphi(n))) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 11 2009]
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CROSSREFS
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Cf. A000005, A000010.
Sequence in context: A060025 A067399 A106737 this_sequence A162897 A103391 A061889
Adjacent sequences: A062818 A062819 A062820 this_sequence A062822 A062823 A062824
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Jul 20 2001
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EXTENSIONS
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Corrected error in offset - Jaroslav Krizek (jaroslav.krizek(AT)atlas.cz Jaroslav Krizek (jaroslav.krizek(AT)atlas.cz), Jul 24 2009
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