  We show that doping-induced charge fluctuations in strongly correlated
Hubbard electron systems near the 1/2-filled, insulating limit cause
overscreening of the electron-electron Coulomb repulsion. The resulting
attractive screened interaction potential supports d_{x^2-y^2}-pairing with a
strongly peaked, doping dependent pairing strength at lower doping, followed by
s-wave pairing at larger doping levels.
