Question 99
Let $p$ be a prime number. Find
$$
1! \cdot 2^2 + 2! \cdot 3^2 + 3! \cdot 4^2 + \dots + (p-3)! \cdot (p-2)^2 \quad \mod p.
$$
$$
1! \cdot 2^2 + 2! \cdot 3^2 + 3! \cdot 4^2 + \dots + (p-3)! \cdot (p-2)^2 \quad \mod p.
$$
MathNet 2014 Question 99
Math Olympiad Vault · MathNet 2014