//   Reihe.java 
import java.io.*;
public class Reihe
{
   public static void main(String[] args) throws IOException
              {
              double s=0.0,a_k=0.0;
              for (int k=0; k<=30; k++)
                  {
                  s=s+Math.pow(2.0/3.0,k); // geometrische Reihe q=2/3
                  System.out.println("n = "+ k +"         S_n = "+ s);
                  }
              }
}