New series representation for Madelung constant
  A new series representation of the Madelung constant is given. We represent Madelung constant as a sum of an exact term plus an exponentially fast converging series. The remarkable result is that even if the series part is discarded, one obtains Madelung constant correct up to ten good decimal figures. This, to the best of our knowledge, may be the fastest converging series representation of the Madelung constant. A few other important identities are also obtained. 
Sandeep Tyagi