RosettaCodeData/Task/Ackermann-function/Clay/ackermann-function.clay

ackermann(m, n) {
    if(m == 0)
      return n + 1;
    if(n == 0)
      return ackermann(m - 1, 1);

    return ackermann(m - 1, ackermann(m, n - 1));
}