  A metastable lattice gas with nearest-neighbor interactions and
continuous-time dynamics is studied using a generalized Becker-Doring approach
in the multidimensional space of cluster configurations. The pre-exponential of
the metastable state lifetime (inverse of nucleation rate) is found to exhibit
distinct peaks at integer values of the inverse supersaturation. Peaks are
unobservable (infinitely narrow) in the strict limit T->0, but become
detectable and eventually dominate at higher temperatures.
