F(a,bλc+λ;z)=2bc+(1/2)(z+12z)λ(λa/2U(a12,αλ)((1+z)cabz1c(αz1)1a+O(λ1))+λ(a1)/2αU(a32,αλ)((1+z)cabz1c(αz1)1a2cb(1/2)(αz1)a+O(λ1))),