Does anyone have a quick proof or reference for the identity:
$$2^{1/4}e^{-\pi/24}=(1+e^{-\pi})(1+e^{-3\pi})(1+e^{-5\pi})\dots$$
It is in Fedor Petrov's comment on an answer here: https://mathoverflow.net/questions/321839/double-sum-over-lattice-points-in-circle
$$2^{1/4}e^{-\pi/24}=(1+e^{-\pi})(1+e^{-3\pi})(1+e^{-5\pi})\dots$$
It is in Fedor Petrov's comment on an answer here: https://mathoverflow.net/questions/321839/double-sum-over-lattice-points-in-circle