Problem - 2721
Simplify the expression $$\binom{2020}{0}^2 + \binom{2020}{1}^2 + \cdots + \binom{2020}{2020}^2$$
Applying the conclusion of # 3976 gives the result as $$\binom{2020\times 2}{2020}=\boxed{\binom{4040}{2020}}$$
Applying the conclusion of # 3976 gives the result as $$\binom{2020\times 2}{2020}=\boxed{\binom{4040}{2020}}$$