public class RecursivePlayOnTheFly 
{
  public static void main (String [] args)

  public static int recursiveS (int n)
  {
    if (n <1)
    {
      System.out.println (" sequence not defined for numbers less than 1 ");
	   return 0;
    }
    else if (n == 1)
      return 2;
    else
      return   2 * recursiveS (n-1);
}
}