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.
(In reply to re: Go on, indeed.
OEIS is a great site. I'm sure I've referenced it more than twice. Have I disparaged using it it in the past? I hope not, I visit there probably once a week.
Just posting a link to OEIS as a solution isn't doing much for the problem, but I feel I went a bit beyond the OEIS sequence. Plus the OEIS sequence is not the same as Ady's - it just contains Ady's.
Posted by Jer
on 2015-05-12 13:25:27