Seven is the only variety D for which the equation 2n − D = x2 has much more than two remedies for n and x pure. Especially, the equation 2n − seven = x2 is recognized as the Ramanujan–Nagell equation. 2 hrs ago By Mashable Staff A MacBook Professional for https://non-slipslippersforelderl55124.digitollblog.com/37705973/not-known-details-about-7-day-pill-organizers