I found a definite integral form of Legendre polynomial of second kind, $$ Q_{n}(z)=\frac{1}{2}\int^{+1}_{-1}\frac{P_{n}(t)}{z-t}dt $$ when n is an integer. I wonder how to evaluate this integral. I tried to use contour integral by changing $t$ to $e^{i\theta}$, but it failed.
I'll appreciate your help.