  The differential transformation method (DTM) enables the easy construction of
a power-series solution to a nonlinear differential equation. The
exponentiation operation has not been specifically addressed in the DTM
literature, and constructing it iteratively is suboptimal. The recurrence for
exponentiating a power series by J.C.P. Miller provides a concise
implementation of exponentiation by a positive integer for DTM. An
equally-concise implementation of the exponential function is also provided.
