  We perform two independent calculations of the two-loop partition function
for the large N 't Hooft limit of the plane-wave matrix model, conjectured to
be dual to the decoupled little string theory of a single spherical type IIA
NS5-brane. The first is via a direct two-loop path-integral calculation in the
matrix model, while the second employs the one-loop dilatation operator of
four-dimensional N = 4 Yang-Mills theory truncated to the SU(2|4) subsector. We
find precise agreement between the results of the two calculations. Various
polynomials appearing in the result have rather special properties, possibly
related to the large symmetry algebra of the theory or to integrability.
