# Sum of products of binomial coefficients

$\large\sum_{i+j+k+l=2016} \binom{505}{i}\binom{505}{j}\binom{505}{k}\binom{505}{l}$ Find the previous sum over all possible quadruples of non-negative integers $$i,\:j,\:k,$$ and $$l,$$ where each one of these indexes is less than or equal to 505, and their sum is 2016 as indicated above.

×

Problem Loading...

Note Loading...

Set Loading...