4193912domain: NAppears in sequencesNumber of points on y^2 + xy = x^3 + x^2 + x over GF(2^n).at n=21A002248Number of points of a Koblitz curve E: y^2 + x*y = x^3 + a*x^2 + 1 over a field with 2^n elements.at n=22A304293