A067583 Integers of the form phi(n^n)/phi(n)^n where phi is the Euler totient function A000010(n).

1, 2, 8, 243, 128, 177147, 32768, 129140163, 94143178827, 2147483648, 50031545098999707, 26588814358957503287787, 19383245667680019896796723, 9223372036854775808, 7509466514979724803946715958257547

Offset

1,2

Links

Table of n, a(n) for n=1..15.

Formula

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)

Mathematica

Select[Table[EulerPhi[n^n]/EulerPhi[n]^n, {n, 100}], IntegerQ] (* Harvey P. Dale, Dec 19 2021 *)

Crossrefs

Sequence in context: A338543 A125264 A028985 * A120378 A012345 A012341

Adjacent sequences: A067580 A067581 A067582 * A067584 A067585 A067586

Keyword

nonn

Author

Benoit Cloitre, Jan 30 2002

Status

approved