Some exact solutions of Friedmann cosmological equation

Abstract: In this paper we present a number of examples of exact solutions for the Friedmann cosmological equation for metric $ F(R) $ gravity model. Emphasis was placed on the possibility of obtaining exact time dependences of the main cosmological physical quantities: scale factor, scalar curvature, Hubble rate and function $ F(R) $. For this purpose an ansatz was used to reduce the Friedmann equation to an ordinary differential equation for function $ F = F(H^{2})$. This made it possible to obtain a number of exact solutions, both already known and new.