Problem 303
25 September 2010
For a positive integer n, define f(n) as the least positive multiple of n that, written in base 10, uses only digits 
2.
Thus f(2)=2, f(3)=12, f(7)=21, f(42)=210, f(89)=1121222.
Also, 
.
Find 
.
For a positive integer n, define f(n) as the least positive multiple of n that, written in base 10, uses only digits 2.
Thus f(2)=2, f(3)=12, f(7)=21, f(42)=210, f(89)=1121222.
Also, .
Find .