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A063070
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Phi(n)-d(n), where d(n) is the number of divisors function (A00005).
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5
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0, -1, 0, -1, 2, -2, 4, 0, 3, 0, 8, -2, 10, 2, 4, 3, 14, 0, 16, 2, 8, 6, 20, 0, 17, 8, 14, 6, 26, 0, 28, 10, 16, 12, 20, 3, 34, 14, 20, 8, 38, 4, 40, 14, 18, 18, 44, 6, 39, 14, 28, 18, 50, 10, 36, 16, 32, 24, 56, 4, 58, 26, 30, 25, 44, 12, 64, 26, 40, 16, 68, 12, 70, 32, 34, 30, 56, 16, 76, 22, 49, 36, 80, 12, 60, 38, 52, 32, 86, 12, 68, 38
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,5
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COMMENTS
| It is known that a(n) >= 1 for n >= 31.
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REFERENCES
| D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, p. 11.
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..1000
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PROG
| (PARI) j=[]; for(n=1, 150, j=concat(j, eulerphi(n)-(numdiv(n)))); j
(PARI) { for (n=1, 1000, write("b063070.txt", n, " ", eulerphi(n) - numdiv(n)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 16 2009]
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CROSSREFS
| Cf. A000010, A000005. A020488 gives n such that a(n) = 0.
Sequence in context: A088251 A140839 A127528 * A049802 A129240 A127786
Adjacent sequences: A063067 A063068 A063069 * A063071 A063072 A063073
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KEYWORD
| easy,sign
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AUTHOR
| Jason Earls (zevi_35711(AT)yahoo.com), Aug 04 2001
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