lpochhammer: Calculate the logarithm of Pochhammer's symbol
Description
lpochhammer returns the value of the natural logarithm of Pochhammer's symbol
calculated as
$$\ln \left[ {\left( z \right)_n } \right] = \ln \Gamma \left( {z + n} \right) - \ln \Gamma \left( z \right)$$
where $\Gamma \left( z \right)$ is the Gamma function