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A067006
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Smallest number for which the totient is divisible by the n-th nontotient number, that is, the n-th term of A007617.
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1
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7, 11, 29, 19, 23, 53, 29, 31, 103, 191, 43, 47, 101, 53, 81, 59, 311, 67, 103, 71, 149, 191, 79, 83, 173, 181, 283, 197, 101, 103, 107, 121, 229, 709, 367, 311, 127, 131, 269, 137, 139, 569, 293, 149, 151, 229, 463, 317, 163, 167, 1021, 173, 349, 179, 181, 547
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OFFSET
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1,1
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LINKS
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FORMULA
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a(n) = min_{x : mod(phi(x), A007617(n)) = 0}. For all nontotient numbers x, q*x+1 is prime with large enough q and a divisor of phi(q*x+1) = q*x is x, the selected nontotient number. [Corrected by Sean A. Irvine, Nov 28 2023]
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EXAMPLE
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14 = A007617(7) is not totient of any other number, but phi(29) = 28 is divisible by 14 and 29 is the smallest number of which the totient is a multiple of 14, so a(7)=29.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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