Fourier coefficients of sextic theta series

This article focuses on the theta series on the 6-fold cover of GL\(_2\). We investigate the Fourier coefficients \(\tau(r)\) of the theta series, and give partially proven, partially conjectured values for \(\tau(\pi)^2\), \(\tau(\pi^2)\) and \(\tau(\pi^4)\) for prime values \(\pi\).