こんにちは! This is my first post so I hope that you like it o(>ω<)o Problem: Is it possible to find positive integers not exceeding , such that all pairwise sums of them are different? Source: IMO ShortList 2001, number theory problem 6 S…

Hi, I'm a rising senior student interested in math olympiad problems especially combinatorics and puzzles in general. I actually have seen many strong Japanese competitors using hatena blog to share a cool problem or a trick they have enco…