MathDB

[a phi function butterfly flies by] Is this brute force? (BMT 2019 Discrete #8)

Source:

May 25, 2019

function

Problem Statement

For a positive integer

n

, define

\phi(n)

as the number of positive integers less than or equal to

n

that are relatively prime to

n

. Find the sum of all positive integers

n

such that

\phi(n) = 20