7 is the only real variety D for which the equation 2n − D = x2 has a lot more than two remedies for n and x natural. Especially, the equation 2n − seven = x2 is called the Ramanujan–Nagell equation. By contrast, once you click a Microsoft-offered ad that https://senioraidtools.com/10-easy-mobility-exercises-for-seniors-to-stay-active-and-independent/