M is a perfect square whose 2nd and 3rd digits are 20 and the last two digits are 16.
Find the three smallest values of M.
Using a bit of brute force I ended up finding the smallest ten values of M.
The square of a number ends in 16 only if the number ends in 04, 46, 54, or 96. I searched by a table using each ending separately. Surprisingly the smallest 3 all come from the last ending.
In order:
1096^2=1201216
4696^2=22052416
9596^2=92083216
10996^2=120912016
14846^2=220403716
14554^2=220641316
17896^2=320266816
17904^2=320553216
20496^2=420086016
20504^2=420414016

Posted by Jer
on 20160407 14:02:58 