I'm working on a problem (specifically, I'm using an exam paper without course notes to prepare for a course starting in September),
Define the partition function $P(q)$ and give its infinite product expression.
Wikipedia has
The generating function for $p(n)$ is given by $$\sum_{n=0}^\infty p(n)x^n=\prod_{k=1}^\infty\left(\frac{1}{1-x^k}\right)$$
But how does this allow us to evalute $p(n)$?