4⁢λ⁢(n+λ+1)⁢(1-x2)⁢Cn(λ+1)⁡(x)=-(n+1)⁢(n+2)⁢Cn+2(λ)⁡(x)+(n+2⁢λ)⁢(n+2⁢λ+1)⁢Cn(λ)⁡(x).