title: Problem 492
date: 2014/12/06 13:00:00
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# [Problem 492](https://projecteuler.net/problem=492)
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[Xem đề gốc (tiếng Anh)](https://projecteuler.net/problem=492)

## **Dãy nổ**

$a_0 = 1$, $a_n = \sum_{k=0}^{n-1} a_k \cdot a_{n-1-k}$. Tính $a(10^6) \pmod{10^9+7}$.

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