The purpose of this note is to prove the following generalization of a result of Polya:
Theorem. Let {an} be a sequence of algebraic integers, and f a nonzero polynomial with complex coefficients. If ∑ n=0∞f(n)anzn is a rational function, then so is ∑ n=0∞anzn.
© Copyright 1965 Pacific Journal of Mathematics. All rights reserved.