MathDB
Prime divisors in a set

Source: Iranian National Olympiad (3rd Round) 2004

January 9, 2009
number theoryleast common multiplenumber theory proposed

Problem Statement

Prove that for any n n, there is a subset {a1,,an} \{a_1,\dots,a_n\} of N \mathbb N such that for each subset S S of {1,,n} \{1,\dots,n\}, iSai \sum_{i\in S}a_i has the same set of prime divisors.