smallest a so that S(n)-S(n+a) = 2018, where S(n)=sum of digits
Source: Lusophon 2018 CPLP P3
September 13, 2018
number theorysum of digitsminimum
Problem Statement
For each positive integer , let be the sum of the digits of . Determines the smallest positive integer such that there are infinite positive integers for which you have .