import java.io.*;

public class exampleIO
{
  public static void main(String[] args) throws IOException
  {
    int x=0;
    
//    for (int i=0; i<20; i++){
//      x+=i;
//      System.out.println(x);
//    }
    
    // Just like Scanner and Random, you can call the PrintWriter whatever you like
    // We'll only ever write or read .txt files. Don't put spaces in the filename.
    
    PrintWriter george = new PrintWriter("TriangularNumbers.txt");
    
    x=0;
    for (int i=0; i<20; i++){
      x+=i;
      george.println(x);
    }
    
    george.close();
    
  }
}