Simple Problem (with sum of first n integers)
Source: Irish MO 2004
May 3, 2012
number theory unsolvednumber theory
Problem Statement
1. (a) For which positive integers n, does 2n divide the sum of the first n positive
integers?
(b) Determine, with proof, those positive integers n (if any) which have the
property that 2n + 1 divides the sum of the first n positive integers.