Seven is the only selection D for which the equation 2n − D = x2 has much more than two methods for n and x organic. Specifically, the equation 2n − 7 = x2 is known as the Ramanujan–Nagell equation. 2 hours back By Mashable Staff A MacBook Professional for https://non-slip-slippers-for-eld85173.therainblog.com/36524396/a-review-of-7-day-pill-organizers