(*  phi_values.nb *)
(* *)
(*  Purpose: *)
(*    Evaluate the phi *)
(*    function at selected argument values, *)
(*    and write the data to a file. *)
(* *)
(*  Modified:  03 February 2006 *)
(*  Author:  John Burkardt *)

nvec = {1,2,3,4,5,6,7,8,9,10,
20,30,40,50,60,100,149,500,750,999 };
fvec = {};
num = Length [ nvec ];

Do [ { n = nvec[[i]], f = EulerPhi[n] ,
fvec = Append [ fvec, f],
      Print["Phi[n]=",N[f,16]] },{i,1,num,1}]

fileout=OpenWrite["C:\\Documents and Settings\\burkardt\\Desktop\\Misc\\mathematica\\phi_values.txt"];
SetOptions[fileout,FormatType->TextForm];
Write[fileout,"#  phi_values.txt"];today=DateList[];Write[fileout,"#  Created on ",today];Write[fileout,"#"];
Write[fileout,"#  n  f"];
Write[fileout,"#"];
Do[{n=nvec[[i]];f=fvec[[i]];Write[fileout,n,"  ",N[f,16]]},{i,1,num,1}];Close[fileout];