Electron-Nuclear potential energy

Write a main program which uses your subroutines to compute the electron-nuclear potential energy for a single electron in the 1s state,

$$V_{\mathrm el-nuc} = \int n(\vec x) V_{\mathrm nuc}(\vec x) ... ...si_{1s}^2(r)\right) \left(-\frac{1}{r}\right) 4 \pi r^2 \, dr.$$

Note: because there is only one electron, $n_{1s}(\vec x)=\psi_{1s}^2(\vec x)$.
Hint: Again, the endpoints of the integration require some care.