Proving the Binomial Identity: A Shorter Solution Approach

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problem
prove that:
[tex]\forall n \in N \forall 0<=k<=2^{n-1} (C(2^n,k)=\sum_{j=0}^{k}C(2^{n-1},j)C(2^{n-1},k-j))[/tex]

attempt at solution
induction seems to be too long I am opting for a shorter solution, so the sum that it's wrriten in the rhs is the square of the sum of the term C(2^(n-1),j) but other than that don't know how to procceed.

any advice?

thanks in advance.
 
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Have you tried using the fact that [tex]2^n=2^{n-1}+2^{n-1}[/tex]
Then expand [tex](1+x)^{2^n}[/tex] in two different ways, equating coefficients of [tex]x^k[/tex]?