[1613] GCD
- 时间限制: 2000 ms 内存限制: 65535 K
- 问题描述
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Given an integer n(1 <= n <= 400000), you need to calculator the sum of all gcd(i, j) for 1 <= i < j <= n.
- 输入
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Each test case contains an integer n.
The last line contains 0, you need not to process it. - 输出
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For each test case, print the sum of of all gcd(i, j) for 1 <= i < j <= n.
- 样例输入
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3 12452
- 样例输出
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3 424642359
- 提示
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无
- 来源
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Alex@NBUT
- 操作
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