seven is the only real variety D for which the equation 2n − D = x2 has a lot more than two remedies for n and x all-natural. Especially, the equation 2n − seven = x2 is recognized as the Ramanujan–Nagell equation.Jahannam has seven gates which might be open up always. (Qur’an – Sura fifteen:forty four). Hell also has seven layers and sin