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 A109660 Numbers n such that the sum of the digits of n^phi(n) is divisible by n. 0

%I

%S 1,2,3,7,9,15,18,27,52,72,261,360,400,3932,4418,7046,7938,8888,9162,

%T 9363,9606,9738,10083,10809,11970,13958,23571,28384,42159,51515

%N Numbers n such that the sum of the digits of n^phi(n) is divisible by n.

%e The digits of 8888^phi(8888) sum to 71104 and 71104 is divisible by 8888, so 8888 is in the sequence.

%t Do[s = n^EulerPhi[n]; k = Plus @@ IntegerDigits[s]; If[Mod[k, n] == 0, Print[n]], {n, 1, 10000}]

%K base,nonn

%O 1,2

%A _Ryan Propper_, Aug 06 2005

%E More terms from _Emeric Deutsch_, Feb 05 2006

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Last modified December 6 21:45 EST 2019. Contains 329809 sequences. (Running on oeis4.)