M⁡(a,b,-z)=12⁢π⁢ⅈ⁢Γ⁡(a)⁢∫-ⅈ⁢∞ⅈ⁢∞Γ⁡(a+t)⁢Γ⁡(-t)Γ⁡(b+t)⁢zt⁢ⅆ⁡t,