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Search: id:A112399
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| A112399 |
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a(n) = sum{1<=k<=n, GCD(k,n)=1} mu(k), where mu(k) = A008683(k) (the Moebius function). |
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+0
2
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| 1, 1, 0, 0, -1, 0, -1, -2, -2, -1, -1, -2, -2, -3, -2, -3, -1, -4, -2, -5, -4, -3, -1, -6, -3, -4, -3, -5, -1, -6, -3, -7, -5, -5, -3, -7, -1, -5, -3, -6, 0, -9, -2, -7, -6, -6, -2, -11, -4, -9, -5, -7, -2, -12, -5, -8, -5, -5, 0, -13, -1, -7, -6, -8, -4, -12, -1, -8, -5, -10, -2, -14, -3, -8, -9, -9, -4, -14, -3, -12, -7, -8, -3, -17
(list; graph; listen)
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OFFSET
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1,8
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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EXAMPLE
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The positive integers <= 10 and coprime to 10 are 1, 3, 7 and 9. So a(10) = mu(1) + mu(3) + mu(7) + mu(9) = 1 - 1 - 1 + 0 = -1.
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PROGRAM
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(PARI) a(n)=sum(k=1, n, if(gcd(n, k)==1, moebius(k), 0)) (Herrgesell)
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CROSSREFS
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Cf. A008683.
Sequence in context: A151552 A160418 A153864 this_sequence A165123 A106180 A055091
Adjacent sequences: A112396 A112397 A112398 this_sequence A112400 A112401 A112402
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KEYWORD
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sign
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AUTHOR
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Leroy Quet Dec 06 2005
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EXTENSIONS
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More terms from Lambert Herrgesell (zero815(AT)googlemail.com) and Matthew Conroy (http://www.madandmoonly.com/doctormatt), Dec 09 2005
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