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Existence of AP of interesting integers

Source: 2018 China TST Day 1 Q2

January 2, 2018
number theoryarithmetic seriesnumber of divisorsChina TST

Problem Statement

A number nn is interesting if 2018 divides d(n)d(n) (the number of positive divisors of nn). Determine all positive integers kk such that there exists an infinite arithmetic progression with common difference kk whose terms are all interesting.