  We formulate and study the microscopic statistical mechanics of systems of
particles with exclusion statistics in a discrete one-body spectrum. The
statistical mechanics of these systems can be expressed in terms of effective
single-level grand partition functions obeying a generalization of the standard
thermodynamic exclusion statistics equation of state. We derive explicit
expressions for the thermodynamic potential in terms of microscopic cluster
coefficients and show that the mean occupation numbers of levels satisfy a
nesting relation involving a number of adjacent levels determined by the
exclusion parameter. We apply the formalism to the harmonic Calogero model and
point out a relation with the Ramanujan continued fraction identity and
appropriate generalizations.
