title: Problem 754
date: 2021/04/04 08:00:00
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# [Problem 754](https://projecteuler.net/problem=754)
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[Xem đề gốc (tiếng Anh)](https://projecteuler.net/problem=754)

## **Tích giai thừa Gauss**

$G_p(n) = \prod_{k=1, \gcd(k,p)=1}^{n} k \pmod{p^2}$. Tính $\sum_{p \le 10^6} G_p(p^2-p)$.

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