title: Problem 915
date: 2024/11/02 12:00:00
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# [Problem 915](https://projecteuler.net/problem=915)
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[Xem đề gốc (tiếng Anh)](https://projecteuler.net/problem=915)

## **GCD khổng lồ**

$f(n) = \gcd(n^n + 1, (n+1)^{n+1} + 1)$. Tính $\sum_{n=1}^{10^7} f(n)$.

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