A four digit number is squared to form an eight digit number. The center four digits of that square form the four digit number. Find all possible four digit numbers.

(If 'abcd' was the four digit number, then the eight digit number would look like 'wxabcdyz'.)

Using Excel, you get two answers:

3792 and 7600.

You could trim if you wanted, only going from 3163 to 9999. Saves about 1/3 of your computation, but I doubt that's an issue.

Posted by Eric on 2004-11-28 16:44:33