last four digits in base 2 are the same as its last four digits in base 5
Source: 2019 Dürer Math Competition Finals Day2 E+14 https://artofproblemsolving.com/community/c1621835_2019_
January 5, 2022
number theorylast digitsDigits
Problem Statement
Let be the set of all positive integers less than whose last four digits in base are the same as its last four digits in base . What remainder do we get if we divide the sum of all elements of by ?