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Search: id:A061091
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| A061091 |
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Number of k with 1 <= k <= n relatively prime to phi(k). |
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+0
1
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| 1, 2, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 16, 16, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 21, 21, 21, 21, 21, 21, 22, 22, 23, 23, 23, 23, 24, 24, 25, 25, 26, 26, 27, 27, 28, 28, 28
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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lim a(n) * ln(ln(ln( n ))) / n = 1 / exp( gamma )
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REFERENCES
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P. Erdos, Some asymptotic formulas in number theory, J. Indian Math. Soc. 12 (1948) 75-78
S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 115-119.
Z. Ruzsa, Erdö s and the integers, J. Number Theory 79 (1999) 115-163.
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LINKS
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S. R. Finch, Euler Totient Function Asymptotic Constants
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FORMULA
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a(n) = sum of GCD( k, phi(k)) = 1 for 0 < k <= n
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CROSSREFS
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Gamma function: A001620, phi function: A000010.
Sequence in context: A073047 A038567 A036234 this_sequence A086592 A132663 A023964
Adjacent sequences: A061088 A061089 A061090 this_sequence A061092 A061093 A061094
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KEYWORD
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nonn,easy
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AUTHOR
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Frank.Ellermann(AT)t-online.de, May 29 2001
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