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%I #10 Dec 19 2021 17:51:03
%S 1,2,8,243,128,177147,32768,129140163,94143178827,2147483648,
%T 50031545098999707,26588814358957503287787,19383245667680019896796723,
%U 9223372036854775808,7509466514979724803946715958257547
%N Integers of the form phi(n^n)/phi(n)^n where phi is the Euler totient function A000010(n).
%F If A007694(n)==0 (mod 3) (or equivalently if A007694(n) = 2^u*3^v with u, v >=1) then a(n) =3^(A007694(n) -1); if A007694(n)=2^u a(n)=2^(A007694(n) -1). Remark : if n=3^v phi(n^n)/phi(n)^n=1/2^(n-1)
%t Select[Table[EulerPhi[n^n]/EulerPhi[n]^n,{n,100}],IntegerQ] (* _Harvey P. Dale_, Dec 19 2021 *)
%K nonn
%O 1,2
%A _Benoit Cloitre_, Jan 30 2002
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