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Search: id:A045763
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| A045763 |
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Number of numbers "unrelated to n": m<n such that m is neither a divisor of n nor relatively prime to n. |
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+0
34
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| 0, 0, 0, 0, 0, 1, 0, 1, 1, 3, 0, 3, 0, 5, 4, 4, 0, 7, 0, 7, 6, 9, 0, 9, 3, 11, 6, 11, 0, 15, 0, 11, 10, 15, 8, 16, 0, 17, 12, 17, 0, 23, 0, 19, 16, 21, 0, 23, 5, 25, 16, 23, 0, 29, 12, 25, 18, 27, 0, 33, 0, 29, 22, 26, 14, 39, 0, 31, 22, 39, 0, 37, 0, 35, 30, 35, 14, 47, 0, 39, 23, 39, 0, 49
(list; graph; listen)
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OFFSET
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1,10
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COMMENT
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a(n)=0 iff n is a prime or 1 or 4. - Robert G. Wilson v (rgwv(at)rgwv.com), Nov 02 2005
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REFERENCES
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Martin Beumer, The Arithmetical Function tau_k(N), Amer. Math. Monthly, 69, Oct 1962, p. 780 (a(n)=ksi(N)).
Suggested by Wouter Meeussen (wouter.meeussen(AT)pandora.be)
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..1000
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FORMULA
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n + 1 - d(n) - phi(n); where d is the number of divisors of n and phi is Euler's totient function.
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MATHEMATICA
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f[n_] := n + 1 - DivisorSigma[0, n] - EulerPhi[n]; Array[f, 84] (* Robert G. Wilson v *)
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CROSSREFS
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Sequence in context: A053387 A141030 A100258 this_sequence A132748 A055945 A138123
Adjacent sequences: A045760 A045761 A045762 this_sequence A045764 A045765 A045766
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(at)rgwv.com), Nov 02 2005
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