Herglotz–Zagier function

In mathematics, the Herglotz–Zagier function, named after Gustav Herglotz and Don Zagier, is the function


 * $$F(x)= \sum^{\infty}_{n=1} \left\{\frac{\Gamma^{\prime}(nx)}{\Gamma (nx)} -\log (nx)\right\} \frac{1}{n}.$$

introduced by who used it to obtain a Kronecker limit formula for real quadratic fields.