Consider the number 4808
Notice: 4^2+8^2=80
i.e. the sum of the squares of this number's first and last digits equals the number obtained when the first and last digits are erased.

How many numbers with such feature exist below 10000?

Clearly, no leading zeroes.

(In reply to re(3): Just counting (spoiler) by Charlie)

Ah, now I understand.  I concur that 83 is the correct answer.

Posted by Steve Herman on 2017-07-18 09:08:51