MathDB
Spring 2020 Team Round Problem 15

Source:

August 22, 2020

Problem Statement

Let ϕ(k)\phi(k) denote the number of positive integers less than or equal to kk that are relatively prime to kk. For example, ϕ(2)=1\phi(2)=1 and ϕ(10)=4\phi(10)=4. Compute the number of positive integers n≤2020n \leq 2020 such that ϕ(n2)=2ϕ(n)2\phi(n^2)=2\phi(n)^2.
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