7^{1998}. -> 1998^7 - All-Russian MO 1998 Regional (R4) 11.5
Source:
September 17, 2024
number theoryDigits
Problem Statement
A whole number is written on the board. Its last digit is remembered is then erased and multiplied by added to the number that remained on the board after erasing. The number was originally written . After applying several such operations, can one get the number ?