The aim of this work is to describe the orthogonal polynomials sequences which are identical to their second associated sequence. The resulting polynomials are semiclassical of class . The characteristic elements of the structure relation and of the second-order differential equation are given explicitly. Integral representations of the corresponding forms are also given. A striking particular case is the case of the so-called electrospheric polynomials.
P. Maroni. M. Ihsen Tounsi. "The second-order self-associated orthogonal sequences." J. Appl. Math. 2004 (2) 137 - 167, 20 June 2004. https://doi.org/10.1155/S1110757X04402058