Dependence of the gap parameter on the number of CuO2 layers in a unit cell of optimally doped BSCCO, TBCCO, HBCCO and HSCCO

We have measured the superconducting gap Ds in optimally doped samples of BSCCO, TBCCO, HBCCO and HSCCO by Andreev and tunnelling spectroscopy and by ARPES. We have found that the low-temperature value of the gap within experimental errors is linearly increasing with the number n of CuO2 layers in the unit cell of the investigated HTSC-families (n < 4)