E. Number Challenge
推式子 ∑i1a∑j1b∑k1cσ(ijk)∑i1a∑j1b∑k1c∑x∣i∑y∣j∑z∣k(gcd(x,y)1)(gcd(x,z)1)(gcd(y,z)1)∑x1a∑y1b∑z1c⌊ax⌋⌊by⌋⌊cz⌋(gcd(x,y)1)(gcd(x,z)1)(gcd(y,z)1)∑d1aμ(d)∑x1⌊ad⌋⌊adx⌋∑y1⌊bd⌋⌊bdy⌋∑z1c⌊cd⌋(gcd(x,z)1)(gcd(y,z…
K Sum
推式子 Fn(k)∑l11n∑l21n⋯∑lk1n(gcd(l1,l2,…,lk))2∑d1nd2∑l11nd∑l21nd⋯∑lk1nd(gcd(l1,l2,…,lk)1)∑d1nd2∑l11nd∑l21nd⋯∑lk1nd∑t∣gcd(l1,l2,…,lk)μ(t)∑d1nd2∑t1ndμ(t)(ntd)2另Ttd∑T1n(nT)k∑d∣Td2μ(Td)∑i2nFn(i)∑T1n∑i2k(nT)i∑d∣Td2μ(Td)到…