A064447 a(n) = phi(n^n).

1, 2, 18, 128, 2500, 15552, 705894, 8388608, 258280326, 4000000000, 259374246010, 2972033482752, 279577021469772, 4762288639524864, 233543408203125000, 9223372036854775808, 778579070010669895696, 13115469358432179191808, 1874292305362402347591138

Offset: 1

Author

Labos Elemer, Oct 02 2001

Keywords

• nonn

Examples

			For p prime, a(p) = (p^(p-1))*(p-1) = ((phi(p)+1)^phi(p))*phi(p).
		

Links

• Harry J. Smith, Table of n, a(n) for n = 1..100

Crossrefs

Cf. A000005, A000010, A000312.

Programs

Mathematica

a[n_]:=EulerPhi[n^n];lst={};Do[AppendTo[lst, a[n]], {n, 0, 2*4!}];lst (* Vladimir Joseph Stephan Orlovsky, Dec 03 2008 *)
Table[EulerPhi[n^n],{n,20}] (* Harvey P. Dale, Jun 02 2015 *)

PARI

a(n) = { eulerphi(n^n) } \\ Harry J. Smith, Sep 14 2009

Formula

a(n) = A000010(A000312(n)).