F⁡(a,1-ac;z)=(1-z-1-1)1-a⁢(1-z-1+1)a-2⁢c+1⁢(1-z-1)c-1⁢F⁡(c-a,c-122⁢c-1;4⁢1-z-1(1-z-1+1)2),