  A study of the effect of deformation and pairing on the development of halo
nuclei is presented. Exploratory three-body $core+n+n$ calculations show that
both the NN interaction and the deformation/excitation of the core hinder the
formation of the halo. Preliminary self-consistent mean-field calculations are
used to search for regions in the nuclear chart where halos could potentially
develop. These are also briefly discussed.
