Hypergeometric 4F1
From specialfunctionswiki
The hypergeometric ${}_4F_1$ function is defined by the series $${}_4F_1(a_1,a_2,a_3,a_4;b_1;z)=\displaystyle\sum_{k=0}^{\infty} \dfrac{(a_1)_k(a_2)_k(a_3)_k(a_4)_k}{(b_1)_k} \dfrac{z^k}{k!},$$ where $(a_1)_k$ denotes the Pochhammer symbol.