We derive a combinatorial multisum expression for the number D(n, k) of partitions of n with Durfee square of order k. An immediate corollary is therefore a combinatorial formula for p(n), the number of partitions of n. We then study D(n, k) as a quasipolynomial. We consider the natural polynomial approximation D~(n,k) to the quasipolynomial representation of D(n, k). Numerically, the sum ∑1≤k≤√n D~(n, k) appears to be extremely close to the initial term of the Hardy-Ramanujan-Rademacher convergent series for p(n).