Weierstrass product for the reciprocal gamma function
= Weierstrass product for the reciprocal gamma function
{c}
The reciprocal gamma function has the entire-product representation
$$
\frac1{\Gamma(z)}
=ze^{\gamma z}\prod_{k=1}^{\infty}
\left(1+\frac zk\right)e^{-z/k}.
$$
This is a particular application of the <Weierstrass factorization theorem>.