SquareNumber Difficult

Problem - 2816
A positive integer $n$ is said to be good if there exists a perfect square whose sum of digits in base $10$ is equal to $n$. For instance, $13$ is good because $7^2 = 49$ and $4 + 9 = 13$. How many good numbers are among $1, 2, 3, \cdots , 2007$?

The solution for this problem is available for $0.99. You can also purchase a pass for all available solutions for $99.

report an error