code: function _gpfPow2 (n) {
      var result = _gpfPow2[n];
      if (result) {
          return result;
      }
      result = _gpfComputePow2(n);
      _gpfPow2[n] = result;
      return result;
  }
docs: Gives the power of 2
  
  @param {Number} n the power to get
  @return {Number}