MathDB

22

Part of 2022 BMT

Problems(1)

BMT 2022 Guts #22

Source:

8/31/2023
Set n=425425n = 425425. Let SS be the set of proper divisors of nn. Compute the remainder when ∑k∈Sϕ(k)(2n/kn/k) \sum_{k\in S} \phi (k) {2n/k \choose n/k} is divided by 2n2n, where ϕ(x)\phi (x) is the number of positive integers at most xx that are relatively prime to it.
number theory