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ROSECODE 165

GCD Harmonic Mean

Philippe_57721 · Math ·

Let's define H(n) = Harmonic mean of GCD(n,k) for k in {1, ... , n}

For the record, if V = {V1, V2, ..., Vn} the harmonic mean of V = n/(1/V1 + 1/V2 + ... + 1/Vn}

Find H(25!)

You are given H(1050) = 52500/22403

Answer format: P/Q

[My timing : 5 sec]