7 is the only selection D for which the equation 2n − D = x2 has in excess of two options for n and x pure. In particular, the equation 2n − seven = x2 is known as the Ramanujan–Nagell equation. We have been including a lot more on a https://senioraidtools.com/10-easy-mobility-exercises-for-seniors-to-stay-active-and-independent/