TITLE: 12th grade - Ramanujan Partition theory
QUESTION [6 upvotes]: I've been really trying to prove Ramanujan Partition theory, and different sources give me different explanations. 
Can someone please explain how Ramanujan (and Euler) found out the following equation for the number of partitions for a given integer?
Any help is appreciated thank you so much!
$$P(n)\sim\frac1{4n\sqrt3}\exp(\pi\sqrt{2n/3})$$

REPLY [3 votes]: Another reference is Atle Selberg's paper "Reflections around the Ramanujan centenary". More precisely, the appendix, if I remember. It appears in the book "Ramanujan: essays and surveys". My recommendation would be to read that before Hardy, for reasons that Selberg himself explains.