See how http://en.wikipedia.org/wiki/Pentagonal_number_theorem http://en.wikipedia.org/wiki/Pentagonal_number_theorem strikes you ;-) At the bottom there's a b

See how http://en.wikipedia.org/wiki/Pentagonal_number_theorem http://en.wikipedia.org/wiki/Pentagonal_number_theorem strikes you ;-) At the bottom there's a bit of Python code for the partition numbers, incidentally.