(F12⁡(a,bc;z))2=∑k=0∞(2⁢a)k⁢(2⁢b)k⁢(c-12)k(c)k⁢(2⁢c-1)k⁢k!⁢F34⁡(-12⁢k,12⁢(1-k),a+b-c+12,12a+12,b+12,32-k-c;1)⁢zk,