IMO 2014 Shortlist N1

Let n ě 2 be an integer, and let An be the set An “ t2n ´ 2k |k P Z, 0 ď k ă nu. Determine the largest positive integer ...

IMO 2014 Shortlist N1

Category: Number Theory

Problem

Let n ě 2 be an integer, and let An be the set An “ t2n ´ 2k |k P Z, 0 ď k ă nu. Determine the largest positive integer that cannot be written as the sum of one or more (not necessarily distinct) elements of An. (Serbia)