2012 IMO Problems/Problem 6

Revision as of 11:46, 21 June 2018 by Illogical 21 (talk | contribs)

Find all positive integers $n$ for which there exist non-negative integers $a_1, a_2, \ldots, a_n$ such that \[\frac{1}{2^{a_1}} + \frac{1}{2^{a_2}} + \cdots + \frac{1}{2^{a_n}} =  \frac{1}{3^{a_1}} + \frac{2}{3^{a_2}} + \cdots + \frac{n}{3^{a_n}} = 1.\]

Proposed by Dusan Djukic, Serbia