Mathematical formula

$\scriptstyle\left(3n+1\right)^2=\left[\left[10\sdot\left[\frac{1}{3}\sdot\left(3n\right)\right]^2\right]-\left[\frac{1}{3}\sdot\left(3n\right)\right]^2\right]+3n+\left(3n+1\right)$

(3n+1)²=((10·(⅓·3n)²)-(⅓·3n)²)+3n+(3n+1) no such category found: mathematical formula