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A058656
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a(n) = gcd(n+1, phi(n)).
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0
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1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 3, 8, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 1, 2, 1, 12, 1, 2, 3, 8, 1, 2, 1, 2, 5, 2, 1, 2, 1, 2, 1, 4, 1, 2, 1, 8, 3, 2, 1, 2, 1, 2, 3, 4, 1, 6, 1, 2, 1, 2, 1, 2, 1, 2, 3, 4, 1, 6, 1, 2, 1, 2, 1, 2, 1, 2, 3, 8, 1, 2, 1, 4, 1, 2, 1, 24, 1, 2, 3, 20, 1, 2, 1
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OFFSET
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1,3
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COMMENTS
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Compare sequences gcd(x, phi(n)), where x = n-1, n, or n+1.
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LINKS
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EXAMPLE
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For n = 12, 13, 14, 15:
n+1 = 13, 14, 15, 16;
phi(n) = 4, 12, 12, 8;
a(n) = gcd(13,4), gcd(14,12), gcd(15,12), gcd(16,8) = 1, 2, 3, 8, respectively.
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MATHEMATICA
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Table[GCD[n+1, EulerPhi[n]], {n, 110}] (* Harvey P. Dale, Nov 17 2011 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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