Bose, Arnab; University of Lethbridge. Faculty of Arts and Science
(Lethbridge, Alta : University of Lethbridge, Dept. of Mathematics and Computer ScienceArts and ScienceDepartment of Mathematics and Computer Science, 2016)

Selfridge asked for what positive integers a and b with a > b, does 2a — 2b divide na — nb for all n e N. The problem was solved by various people who showed that the above problem is true only for (a, b) e S, where S ...