16 is the smallest 2-digit square whose digits are non-decreasing.
144 is the smallest 3-digit square whose digits are non-decreasing.
1156 is the smallest 4-digit square whose digits are non-decreasing.

GO ON!

(In reply to re(2): Go on, indeed. by Jer)

Jer,

You may not remember this:

http://perplexus.info/show.php?pid=9673&cid=54668

Posted by broll on 2015-05-13 05:02:09