Freaks City

Dirichlet Convolution Dirichlet convolution is a binary operation defined between arithmetic functions. It can be expressed as \((f * g)(n) = \sum_{xy = n} f(x) \cdot g(y)\) or equivalently \((f * g)(n) = \sum_{d \mid n} f(d) \cdot g(\frac{n}{d})\). Properties If both \(f\) and \(g\) are multiplicative functions, then \(f * g\) is also multipl ...