How would i show the following:
The number of partitions of the integer n into 3 parts is equal to the number of partitions of 2n into 3 parts of size less than n.
I've tried drawing the Ferrers diagram, but I can't seem to extract any useful information.
I am pretty sure the generating function for the number of partitions of the integer n into 3 parts is:
but I am not sure how to get the other generating function.
Thank you for your help.