@**techreport**{RISC6013,author = {Christian Krattenthaler and Mircea Merca and Cristian-Silviu Radu},

title = {{Infinite Product Formulae for Generating Functions for Sequences of Squares}},

language = {english},

abstract = {We state and prove product formulae for several generating functions for sequences (an)n>=0 that are defined by the property that Pan+b2 is a square, where P and b are given integers. In particular, we prove corresponding conjectures of the second author. We show that, by means of the Jacobi triple product identity, all these generating functions can be reduced to a linear combination of theta function products. The proof of our formulae then consists in simplifying these linear combinations of theta products into single products. We do this in two ways: (1) by the use of modular function theory, and (2) by applying the Weierstraß addition formula for theta products.
},

year = {2019},

keywords = {modular functions, generalized eta quotient identities},

length = {37},

license = {CC BY 4.0 International},

type = {RISC Report Series},

institution = {Research Institute for Symbolic Computation (RISC), Johannes Kepler University Linz},

address = {Altenberger Straße 69, 4040 Linz, Austria},

issn = {2791-4267 (online)}

}