On a relation between certain $q$-hypergeometric series and Maass waveforms

Abstract

In this paper, we answer a question of Li, Ngo, and Rhoades concerning a set of $q$-series related to the $q$-hypergeometric series $\sigma$ from Ramanajun's lost notebook. Our results parallel a theorem of Cohen which says that $\sigma$, along with its partner function $\sigma^*$, interpolate the coefficients of a Maass waveform of eigenvalue $1/4$.