\[\left.\frac{\partial Y_{\nu}\left(z\right)}{\partial\nu}\right|_{\nu=n}=-\frac%
{\pi}{2}J_{n}\left(z\right)+\frac{n!}{2(\tfrac{1}{2}z)^{n}}\sum_{k=0}^{n-1}%
\frac{(\tfrac{1}{2}z)^{k}Y_{k}\left(z\right)}{k!(n-k)},\]