M.A. Gopalan, K. Geetha, Manju Somanath, Special Dio 3 - Tuples, BSMaSS Volume 10, The Bulletin of Society for Mathematical Services and Standards (Volume 10)
https://www.scipress.com/BSMaSS.10.22
Abstract:
    We search for three distinct polynomials with integer coefficient such that the product of anytwo members of the set minus their sum and increased by a non-zero integer (or polynomial withinteger coefficient) is a perfect square.
Keywords:
    Centered Polygonal Numbers, Dio 3 - Tuples, Pell Equation, Polygonal Numbers