Eta product for mf.14.2.1.a (awaiting review)

This cusp form can be expressed as an eta product $\eta(z)\eta(2z)\eta(7z)\eta(14z)=q\prod_{n=1}^\infty(1-q^n)(1-q^{2n})(1-q^{7n})(1-q^{14n})$, where $q=e^{2\pi iz}$.