We ask users to provide proof(s), reference(s) to proof(s), or further clarification on the proof(s) in this space.
: ultraspherical/Gegenbauer polynomial : http://dlmf.nist.gov/18.3#T1.t1.r5
: Pochhammer symbol : http://dlmf.nist.gov/5.2#iii
Equation in Section 9.8 of KLS.
We ask users to provide relevant URL links in this space.