Let \( Q \) and \( R \) be two points on the line \(\displaystyle \frac{x+1}{2}=\frac{y+2}{3}=\frac{z-1}{2} \) at a distance \( \sqrt{26} \) from the point \( P(4,2,7) \). Then the square of the area of the triangle \( PQR \) is ________.
