Atoms among 100 digit numbers
Source: Romania TST 3 2012, Problem 4
May 11, 2012
inductionvectorcombinatorics proposedcombinatorics
Problem Statement
Let be a set of positive integers, each of them having exactly digits in base representation. An element of is called atom if it is not divisible by the sum of any two (not necessarily distinct) elements of . If contains at most atoms, at most how many elements can have?