What are all integers n such that 840n2−4200n+5041 is the square of an integer?

Answer 1

The discriminant must be zero

(-4200n)^2 - 4(840n)(5041) = 0

17640000n^2 - 16937760n = 0

n( 17640000 - 16937760) = 0

n=0 or n = 16937760/17640000