How to solve a problem in C++ for algorithms?

Question

C++ / C#

Natural numbers a and b are given (a<=b ). Write a program to print all numbers from a to b whose squares are equal to their binomial coefficient. Those. k^2+n^2=n!/(k!(nk)!).

It seems easy, I just don't understand what k^2+n^2=n!/(k!(nk)!) means and where to get it from the square of a number.

Answer 1

Apparently, we need to print all pairs n and k such that k^2+n^2=n!/(k!(nk)!), a <= k <= n <= b.