7 is the only real range D for which the equation 2n − D = x2 has in excess of two answers for n and x all-natural. Especially, the equation 2n − seven = x2 is referred to as the Ramanujan–Nagell equation. Not everyone thinks that cats have 9 life. https://non-slipslippersforelderl84447.like-blogs.com/37602809/everything-about-7-day-pill-organizers