Monday, February 21, 2011

a 9-digit number such that

Make a 9-digit number of the digits 1, ... ,9 such that
the number created by the first n digits is divisible by n.

Prove that the solution is unique.

1 comment:

  1. The number is 381654729.

    I can show that it is unique by testing all possible values between 123456789 and 987654321 and that is the only solution. It isn't a mathematical proof I know.