Let N1=123456789
Erase n digits and shrink the remnants of N1 into one continuous chain creating a new number N1'.

What is the minimum number of digits to be erased so that N1' will be a square number?

Same question for N2=987654321 and N2'.

(In reply to Solution by cheating by Jer)

For the second, you must mean A124683

Posted by Charlie on 2018-04-05 14:51:50