MathDB
Indonesia National Science Olympiad 2010 - Day 2 Problem 6

Source:

September 28, 2010
number theoryrelatively primenumber theory unsolved

Problem Statement

Find all positive integers n>1n>1 such that τ(n)+ϕ(n)=n+1\tau(n)+\phi(n)=n+1 Which in this case, τ(n)\tau(n) represents the amount of positive divisors of nn, and ϕ(n)\phi(n) represents the amount of positive integers which are less than nn and relatively prime with nn.
Raja Oktovin, Pekanbaru
Back to ProblemsView on AoPS