  The Hall coefficient exhibits anomalous behavior in lightly doped Mott
insulators. For strongly interacting electrons its computation has been
challenged by analytical and numerical obstacles. We calculate the leading
contributions in the recently derived thermodynamic formula for the Hall
coefficient. We obtain its doping and temperature dependence for the square
lattice tJ-model at high temperatures. The second order corrections are
evaluated to be negligible. Quantum Monte Carlo sampling extends our results to
lower temperatures. We find a divergence of the Hall coefficient toward the
Mott limit and a sign reversal relative to Boltzmann equation's weak scattering
prediction. The Hall current near the Mott phase is carried by a low density of
spin-entangled vacancies, which should constitute the Cooper pairs in any
superconducting phase at lower temperatures.
