∑(2⁢n)!(2⁢j)!⁢(2⁢k)!⁢(2⁢ℓ)!⁢(2⁢m)!⁢B2⁢j⁢B2⁢k⁢B2⁢ℓ⁢B2⁢m=-(2⁢n+33)⁢B2⁢n-43⁢n2⁢(2⁢n-1)⁢B2⁢n-2.