Sum of the squares of first n odd numbers = $\dfrac{n(2n + 1)(2n - 1)}{3}$
Sum of squares of first 75 odd numbers = $\dfrac{75 × (2 × 75 + 1)(2 × 75 - 1)}{3}$
= $\dfrac{75 × 151 × 149}{3}$
= 562475