# Tag Info

J, 18 bytes */@,@(1+%)1++/&i./ Try it online! Takes z on its left and x y on the right. Uses modified formula by Peter Taylor:  \begin{align} \prod_{i=1}^x \prod_{j=1}^y \frac{i+j+z-1}{i+j-1} &= \prod_{i=1}^x \prod_{j=1}^y \left(1 + \frac{z}{i+j-1}\right) \\ &= \prod_{i=0}^{x-1} \prod_{j=0}^{y-1} \left(1 + \frac{z}{i+j+1}\right) \end{align}...