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A067006 Smallest number for which the totient is divisible by the n-th nontotient number, that is, the n-th term of A007617. 0

%I

%S 7,11,29,19,23,53,29,31,103,191,43,47,101,53,81,59,311,67,103,71,149,

%T 191,79,83,173,181,283,197,101,103,107,121,229,709,367,311,127,131,

%U 269,137,139,569,293,149,151,229,463,317,163,167,1021,173,349,179,181,547

%N Smallest number for which the totient is divisible by the n-th nontotient number, that is, the n-th term of A007617.

%F a(n) = min_{x : mod(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.

%e 14 = A007617(7) is not totient of any other number, but phi(29) = 28 is divisible with 14 and 29 is the smallest number of which the totient is a multiple of 14, so a(7)=29.

%Y Cf. A000010, A007617, A066674-A066678, A067005.

%K nonn

%O 1,1

%A _Labos Elemer_, Dec 22 2001

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Last modified February 24 04:36 EST 2020. Contains 332197 sequences. (Running on oeis4.)