  We show that inflation and current cosmic acceleration can be generated by a
metric-affine f(R) gravity formulated in the Einstein conformal frame, if the
gravitational Lagrangian L(R) contains both positive and negative powers of the
curvature scalar R. In this frame, we give the equations for the expansion of
the homogeneous and isotropic matter-dominated universe in the case
L(R)=R+{R^3}/{\beta^2}-{\alpha^2}/{3R}, where \alpha and \beta are constants.
We also show that gravitational effects of matter in such a universe at very
late stages of its expansion are weakened by a factor that tends to 3/4, and
the energy density of matter \epsilon scales the same way as in the \Lambda-CDM
model only when \kappa*\epsilon<<\alpha.
