Seven is the only real variety D for which the equation 2n − D = x2 has a lot more than two options for n and x organic. Particularly, the equation 2n − 7 = x2 is referred to as the Ramanujan–Nagell equation. 2 several hours back By Mashable Staff https://senioraidtools.com/10-easy-mobility-exercises-for-seniors-to-stay-active-and-independent/