7 is the sole range D for which the equation 2n − D = x2 has over two methods for n and x organic. Specifically, the equation 2n − 7 = x2 is named the Ramanujan–Nagell equation.Of course There exists also the properly-known story of Pharaohs desire in regards to the 7 fat cows and 7 thin cows.The 7 classical planets resulted in seven remainin