  We present ab-initio calculations for 3H, 4He, 16O, and 40Ca based on
two-nucleon low-momentum interactions Vlowk within coupled-cluster theory. For
3H and 4He, our results are within 70 keV and 10 keV of the corresponding
Faddeev and Faddeev-Yakubovsky energies. We study in detail the convergence
with respect to the size of the model space and the single-particle basis. For
the heavier nuclei, we report practically converged binding energies and
compare with other approaches.
