k | a_1+\dots+a_k
Source: All-Russian olympiad 1995, Grade 10, First Day, Problem 3
October 21, 2013
modular arithmeticalgorithmnumber theory proposednumber theory
Problem Statement
Does there exist a sequence of natural numbers in which every natural number occurs exactly once, such that for each the sum of the first terms of the sequence is divisible by ?
A. Shapovalov