Optimum choice of the parameters in the Mittag-Leffler expansion for a given region of observation

A determination is reported of the parameters of the Mittag-Leffler expansion that result in the optimum expansion for the reciprocal distance that converges more rapidly tban the universal expansion by the factor $e^{20/l_1^2}$, where $l_1$ is the distance between the nearest mountains and the point of observation. The expansion converges more rapidly at a given point than the Laplace series.