  This paper presents a comprehensive study of a class of functions which
approximate 1/|x| for large x but which are finite at the origin. These
functions arise naturally in the study of atoms in strong magnetic fields where
the so-called "Landau states" give rise to Gaussian integrals. Generalizations
in which e^{-x^2} is replaced by e^{-x^p} are also considered and approximate
x^{1-p} for large x.
  The limiting behavior and monotonicity properties of these functions are
discussed in terms of parameters which arise in the approximations as well as
x. Several classes of inequalities, some of which provide tight bounds, are
established. Some differential equations and recursion relations satisfied by
these functions are given. The recursion relations give rise to two classes of
polynomials, one of which is related to confluent hypergeometric functions.
Finally, it is shown that the inverse of the approximating function is convex
and this implies an analogue of the triangle inequality. Some comments are made
about possible extensions and several open questions are raised.
