All the nine digits are arranged here so as to form four square numbers.
9, 81, 324, 576
Which is the single smallest possible square number and a single largest possible square number using all the 9 digits exactly once?
What are the possible two, three & four number sets that follow this logic?
(In reply to
computer solution (spoiler) by Charlie)
The pandigtal pairs of squares has some surprising features.
Among pairs with a one digit square there are five that use a 9 but none that use a 1 or a 4. Why should there be such a difference in eight digit squares that don't repeat a digit?
(Charlie, maybe you could try excluding the other digits)
Among pairs with two digit squares, only 36 (two) and 81 (four) are represented. Again, why not 16, 25, 49, 64?

Posted by Jer
on 20061013 07:30:37 