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Search: id:A062816
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| -1, -2, -2, -2, -2, -4, -2, 0, 0, -4, -2, 0, -2, -4, 2, 8, -2, 0, -2, 8, 6, -4, -2, 16, 10, -4, 18, 16, -2, 4, -2, 32, 14, -4, 26, 36, -2, -4, 18, 48, -2, 12, -2, 32, 54, -4, -2, 64, 28, 20, 26, 40, -2, 36, 50, 80, 30, -4, -2, 72, -2, -4, 90, 96, 62, 28, -2, 56, 38, 52, -2, 144, -2, -4, 90, 64, 86, 36, -2, 160, 108, -4, -2, 120, 86, -4
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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It can be shown that Phi[n]*Tau[n]>=n, which means that quotient=n/Tau[n]<=Phi[n]; note: a(n)+5 is positive;
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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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EXAMPLE
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The value is always positive except when a(n)=0 for {8,9,12}; or a(n)=-2 for primes together with 4 (i.e. for A046022 but without 1); or a(n)=-4 for A001747 (without 2 and 4); or a(n)=-1 for n=1
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PROGRAM
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(PARI) { for (n=1, 2000, write("b062816.txt", n, " ", eulerphi(n)*numdiv(n) - 2*n) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 11 2009]
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CROSSREFS
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Cf. A000010, A000005, A062516, A046022, A001747, A036762, A036763, A051728, A051729, A051730.
Sequence in context: A125914 A086668 A092904 this_sequence A122857 A132003 A109810
Adjacent sequences: A062813 A062814 A062815 this_sequence A062817 A062818 A062819
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KEYWORD
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sign
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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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OFFSET changed from 0,2 to 1,2 by Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 11 2009
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