code: private static int[] sequence(int e) {
      int[] a = new int[e];
      for(int i = 0; i < a.length; i++) {
        a[i] = i;
      }
      return a;
    }
docs: Generate the integer sequence 0 .. e-1
  <p>
  TODO: move to shared code.
  
  @param e End (exclusive)
  @return End