Seven is the sole quantity D for which the equation 2n − D = x2 has a lot more than two options for n and x pure. Especially, the equation 2n − seven = x2 is recognized as the Ramanujan–Nagell equation. Certainly There's also the properly-known Tale of Pharaohs desire https://non-slipslippersforelderl53840.blognody.com/42866582/the-7-day-pill-organizers-diaries