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APMO 2016 #2

Posted: Fri Aug 05, 2016 10:11 am
by Zawadx
A positive integer is called fancy if it can be expressed in the form $$2^{a_1}+2^{a_2}+ \cdots+ 2^{a_{100}},$$where $a_1,a_2, \cdots, a_{100}$ are non-negative integers that are not necessarily distinct. Find the smallest positive integer $n$ such that no multiple of $n$ is a fancy number.