Multiple gamma function
From specialfunctionswiki
Define $$\Gamma_N(w|a_1,\ldots,a_N)=\exp \left( \dfrac{\partial}{\partial s} \zeta_N(s,,w|a_1,\ldots,a_N)\big|_{s=0} \right),$$ where $\zeta_N$ denotes the Barnes zeta function.
