Hello
i really need to solve this problem and i really apprecitae if anyone could help me to find the way:

1. The problem statement, all variables and given/known data
write the following serie (the picture attached) in the form of hypergeometric function.
n changes from 0 to infinity.


2. Relevant equations
hypergeometric function:



3. The attempt at a solution
guys i have thought about this for 2 hours,and i had not any initial idea how to solve it,i appreciate if anyone could give me an initial idea that how should i solve this problem

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