## Power series that I cant crack

Hi,

I wonder if anyone can arrive at a closed form for the following power series.

$\sum_{t=1}^{\infty} q^{(t-1)(2t-1)} - q^{t(2t-1)}$

where 0<q<1

Numerically, it equals 0.5239 when q = 5/6 for example, but I'd love to know if a closed form exists for it.