Commit 2025-11-24 19:10 0cba3cbe

feat: sums of convolutions of arithmetic functions (#31705) Adds results about the sum of the Dirichlet convolution of arithmetic functions: this is equal to the sum over suitable pairs of natural numbers and also to the sum of one function times the partial sum of the other. Specializing to the arithmetic function zeta this gives an O(N) formula for the sum of the number of divisors function. These results are a first step if we want to give asymptotics for various sums of arithmetic functions and for proving the Chebyshev and Mertens theorems.