  Using the Tc formula given by BCS, together with a shear modulus varying with
the numbering of planes, we can demonstrate that Tc oscillates depending on the
number of the cuprate planes. The maximum of Tc in these oscillations appears
for three planes irrespective of the cuprate family. Comparison with
experimental data shows good agreement and suggests that the electron-phonon
coupling predominate in the superconductivity of these materials. This model
predicts that such oscillations can also occur in many others physical
quantities that depend on Tc. The new Tc formula shows interesting prospects
towards room temperature superconductors.
