  We study the H^n-Yamabe constants of Riemannian products (H^n \times M^m,
g_h^n +g), where (M,g) is a compact Riemannian manifold of constant scalar
curvature and g_h^n is the hyperbolic metric on H^n. Numerical calculations can
be carried out due to the uniqueness of (positive, finite energy) solutions of
the equation \Delta u -\lambda u + u^q =0 on hyperbolic space H^n under
appropriate bounds on the parameters \lambda, q, as shown by G. Mancini and K.
Sandeep. We do explicit numerical estimates in the cases (n,m)=(2,2),(2,3) and
(3,2).
