Is There a Simple Programmable Form of Multinomial Expansion?

[EngWiPy]

Hello,

Is there a simple programmable form of multinomial expansion, like a summation with explicit and clear lower and upper limits?

Regards

 

[mathman]

It is a little messy. The general term is (n!/[m1!m2!...mk!])a1^m1a2^m2...ak^mk. The sum limits are all mj >=0 and m1+m2+...+mk=n.

To simplify typing all aj and mj should be thought of as being subscripted. k is the total number of variables.