Problem

Source: IMO ShortList 1990, Problem 1 (AUS 3)

Tags: number theory, Additive combinatorics, Additive Number Theory, counting, IMO Shortlist



The integer $ 9$ can be written as a sum of two consecutive integers: $ 9 = 4+5.$ Moreover, it can be written as a sum of (more than one) consecutive positive integers in exactly two ways: $ 9 = 4+5 = 2+3+4.$ Is there an integer that can be written as a sum of $ 1990$ consecutive integers and that can be written as a sum of (more than one) consecutive positive integers in exactly $ 1990$ ways?