# An interesting equality

Calcul the sum is a very interesting subject, so I present to you this one. Can you solve it ?:D

Prove that: $$\forall{n}\in{N}$$, $$\displaystyle \sum_{i+j=n}C^i_n(i+1)^{i-1}(j+1)^{j-1}=2(n+2)^{n-1}$$.

Note by Quan Dinh
5 years, 6 months ago

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go with pmi i.e principal of mathematical induction

- 5 years, 6 months ago

Can you write it down more clearly? Thanks!

- 5 years, 6 months ago

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