MathDB
Repeated difference sequences cover the positive integers

Source: KoMaL A. 872

March 12, 2024
algebracombinatoricsSequencekomal

Problem Statement

For every positive integer kk let ak,1,ak,2,a_{k,1},a_{k,2},\ldots be a sequence of positive integers. For every positive integer kk let sequence {ak+1,i}\{a_{k+1,i}\} be the difference sequence of {ak,i}\{a_{k,i}\}, i.e. for all positive integers kk and ii the following holds: ak,i+1ak,i=ak+1,ia_{k,i+1}-a_{k,i}=a_{k+1,i}. Is it possible that every positive integer appears exactly once among numbers ak,ia_{k,i}?
Proposed by Dávid Matolcsi, Berkeley