  The corner transfer matrix renormalization group method is an efficient
method for evaluating physical quantities in statistical mechanical models. It
originates from Baxter's corner transfer matrix equations and method, and was
developed by Nishino and Okunishi in 1996. In this paper, we review and adapt
this method, previously used for numerical calculations, to derive series
expansions. We use this to calculate 92 terms of the partition function of the
hard squares model. We also examine the claim that the method is subexponential
in the number of generated terms and briefly analyse the resulting series.
