50202571769domain: NAppears in sequencesa(n) = denominator of y-coordinate of (2n)*P where P is the generator for rational points on the curve y^2 + y = x^3 - x.at n=8A028939Denominator of y coordinate of n*P where P is the generator [0,0] for rational points on curve y^2+y = x^3-x.at n=17A028943