7 is the only number D for which the equation 2n − D = x2 has much more than two options for n and x normal. In particular, the equation 2n − seven = x2 is known as the Ramanujan–Nagell equation. The island of Ogygia was the home of The https://juliusiedwo.gynoblog.com/36741903/7-day-pill-organizers-options