7 is the one selection D for which the equation 2n − D = x2 has greater than two remedies for n and x all-natural. In particular, the equation 2n − seven = x2 is recognized as the Ramanujan–Nagell equation. Jahannam has 7 gates which are open up always. (Qur’an https://nigelg368gog5.vigilwiki.com/user