  A D-dimensional gravitational model with Gauss-Bonnet term is considered.
When ansatz with diagonal cosmological type metrics is adopted, we find
solutions with exponential dependence of scale factors (with respect to
"synchronous-like" variable) which describe an exponential expansion of "our"
3-dimensional factor-space and obey the observational constraints on the
temporal variation of effective gravitational constant G. Among them there are
two exact solutions in dimensions D = 22, 28 with constant G and also an
infinite series of solutions in dimensions D \ge 2690 with the variation of G
obeying the observational data.
