solved equations of this type with A = 1 and 1 ≤ D ≤ 100. In particular, the following generalization of the Ramanujan-Nagell equation: has positive integer solutions only when x = 1, 3, 5, 11, or 181. See also Pillai's conjecture Scientific equations named after people Notes References External links Can N2 + N + 2 Be A Power Of 2?, Math Forum discussion Diophantine equations Srinivasa Ramanujan