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d(n)+d(n+1)=5

Source: Canadian Repêchage 2012: Problem 2

May 19, 2014
modular arithmeticnumber theory proposednumber theory

Problem Statement

Given a positive integer mm, let d(m)d(m) be the number of positive divisors of mm. Determine all positive integers nn such that d(n)+d(n+1)=5d(n) +d(n+ 1) = 5.
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