  We consider the vacuum expectation values of 1/2-BPS circular Wilson loops in
N=4 super Yang-Mills theory in the totally antisymmetric representation of the
gauge group U(N) or SU(N). Localization and matrix model techniques provide
exact, but rather formal, expressions for these expectation values. In this
paper we show how to extract the leading and sub-leading behavior in a 1/N
expansion with fixed 't Hooft coupling starting from these exact results. This
is done by exploiting the relation between the generating function of
antisymmetric Wilson loops and a finite-dimensional quantum system known as the
truncated harmonic oscillator. Sum and integral representations for the 1/N
terms are provided.
