\[\left(z\frac{\mathrm{d}}{\mathrm{d}z}z\right)^{n}\left(e^{-\frac{1}{2}z}z^{%
\kappa-1}W_{\kappa,\mu}\left(z\right)\right)=(-1)^{n}e^{-\frac{1}{2}z}z^{%
\kappa+n-1}W_{\kappa+n,\mu}\left(z\right).\]