给n,k n,kn,k,求: ∑a1=1k∑a2=1k...∑an=1kgcdmod109+7sum_{a_1=1}^k sum_{a_2=1}^k...sum_{a_n=1}^k {gcd} mod 10^9+7∑a1=1k∑a2=1k...∑an=1kgcdmod109+7
给 n,k n,k n,k,求: ∑a1=1k∑a2=1k...∑an=1kgcd(a1,a2...an) mod 109+7sum_{a_1=1}^k sum_{a_2=1}^k...sum_{a_n=1}^k {gcd(a_1,a_2...a_n)} mod 10^9+7∑a1=1k∑a2=1k...∑an=1kgcd(a1,a2...an) mod 109+7
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