Browse · MATH
Printjmc
number theory senior
Problem
A certain integer has digits when written in base . The same integer has digits when written in base . What is the sum of all possible values of ?
Solution
The smallest integer that has digits in base is , which stands for . The largest integer that has digits in base is , which is less than and therefore stands for .
Thus, when a -digit base- integer is written in base , its highest place value is either , , or . It follows that the base- expression has , , or digits, so the sum of all possible values for is .
Thus, when a -digit base- integer is written in base , its highest place value is either , , or . It follows that the base- expression has , , or digits, so the sum of all possible values for is .
Final answer
33