By induction I can prove : $$\sum^{M}_{t=0}\frac{(t+D-1)!}{t!(D-1)!} = \frac{(D+M)!}{D!M!} $$
However, I couldn't derive the right hand side directly.
It would be of great help if anyone can solve it!!
By induction I can prove : $$\sum^{M}_{t=0}\frac{(t+D-1)!}{t!(D-1)!} = \frac{(D+M)!}{D!M!} $$
However, I couldn't derive the right hand side directly.
It would be of great help if anyone can solve it!!