nim[0] = 0, nim[1] = 1;
i = 2..n,
  b = {0..i}
  j = 0..i
  {
    left = max(0, j-1);
    right = max(0, i - j -2);
    v = nim[left] ^ nim[right];
    exclude (b, v)
  }
  nim[i] = min{x, which, x in b}
 ......
Is This way  right?