∏k=0∞a1+k⁢a2+k⁢⋯⁢am+kb1+k⁢b2+k⁢⋯⁢bm+k=Γ⁡b1⁢Γ⁡b2⁢⋯⁢Γ⁡bmΓ⁡a1⁢Γ⁡a2⁢⋯⁢Γ⁡am,