Implications of extreme flatness in a general f ( R ) theory

We discuss a modified gravity theory defined by f (R) = l n n M 2(1-n) R n . We consider both finite and infinite number of terms in the series while requiring that the Einstein frame potential of the theory has a flat area around any of its stationary points. We show that the requirement of maximally flat stationary point leads to the existence of the saddle point (local maximum) for even (odd) l. In both cases for l one obtains the Starobinsky model with small, exponentially suppressed corrections.