Find all integers n such that S(n) = S(2n) = ... = S(n*n), where S is the sum of the base-10 digits.
(In reply to computer exploration--no proof
Well, that suffered from lack of precision.
With DEFDBL A-Z, we see that 9999 as well as 99999 and 999999 and 9999999 also work.
I'm assuming it works for all 10^k-1.
Posted by Charlie
on 2012-11-22 12:14:06