Mathematical formula

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

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