IMO Shortlist 1967 problem 1
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arhiva2. travnja 2012. Prove that all numbers of the sequence

are exact cubes.
%V0
Prove that all numbers of the sequence $$\frac{107811}{3}, \quad \frac{110778111}{3}, \frac{111077781111}{3}, \quad \ldots$$ are exact cubes.
Izvor: Međunarodna matematička olimpijada, shortlist 1967