Mittag-Leffler Expansion for Tangent Function

Theorem

 * $\displaystyle \pi \tan \paren {\pi z} = 8 \sum_{n \mathop = 0}^\infty \frac z {\paren {2 n + 1}^2 - 4z^2}$

where:
 * $z \in \C$ is not a half-integer
 * $\tan$ is the tangent function.