  It is known that Gauss-Bonnet terms in higher dimensional gravity can produce
an effective cosmological constant. We add extra examples to this picture by
presenting explicitly two branches of accelerating vacuum solutions to the
Einstein-Gauss-Bonnet gravities with a bare cosmological constant in 5 and 6
dimensions. Both branches of solutions are of constant curvature and the
effective cosmological constants are independent of the acceleration parameter.
One branch (the "-" branch) of the solutions is well defined in the limit when
the Gauss-Bonnet parameter approaches zero, in which case the effective
cosmological constant becomes identical with the bare value, while the other
(i.e. the "+") branch is singular in the same limit, and beyond this singular
limit, the effective cosmological constant is inversely proportional to the
Gauss-Bonnet parameter with a negative constant of proportionality when the
bare value vanishes.
