  We have measured the current(I)-voltage(V) characteristics of a single-wall
carbon nanotube quantum dot coupled to superconducting source and drain
contacts in the intermediate coupling regime. Whereas the enhanced differential
conductance dI/dV due to the Kondo resonance is observed in the normal state,
this feature around zero bias voltage is absent in the superconducting state.
Nonetheless, a pronounced even-odd effect appears at finite bias in the $dI/dV$
sub-gap structure caused by Andreev reflection. The first-order Andreev peak
appearing around V=\Delta/e is markedly enhanced in gate-voltage regions, in
which the charge state of the quantum dot is odd. This enhancement is explained
by a `hidden' Kondo resonance, pinned to one contact only. A comparison with a
single-impurity Anderson model, which is solved numerically in a slave-boson
meanfield ansatz, yields good agreement with the experiment.
