GCD problem
Practice
4 (47 votes)
Medium Hard
Mobius inversion
Number theory
Mathematics
Greatest common divisor
Problem
45% Success 6742 Attempts 50 Points 5s Time Limit 256MB Memory 1024 KB Max Code
For each set of four integers given \((i,j ,k,l)\) where \(1\leq i < j <k <l \leq N\). You are required to compute the following:
\(\displaystyle\sum_{i=1}^{N} \displaystyle\sum_{j=i+1}^{N}\displaystyle\sum_{k=j+1}^{N} \displaystyle\sum_{l=k+1}^{N} gcd(i,j,k,l) ^{4}\)
Input format
- First line: \(T\) that denotes the number of test cases
- Next \(T\) lines: A integer \(N\)
Output format
Print the answer for each test case \(Mod \,\,\,10^9+7\) in a new line.
Constraints
\(1 \leq T \leq 10 \\ 1 \leq N \leq 10^5\)
Submissions
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