Rational points on elliptic curves over the rationals ellrank ? E = ellinit([0,-1,0,-260,-1530]); ? ellrank(E) %8 = [1,3,[[27,102]]] Here the rank is either 1 or 3 and one point is known. Here the conductor is small so we can check the analytic rank: ? A=ellanalyticrank(E) %9 = [1,4.2585990440444049230727399816153311674] We find that the analytic rank is 1 so the rank is 1 and we have a Q-basis, and ØE is even ? A[2]/ellbsd(E)/ellheight(E,[27,102]) %10 = 4.0000000000000000000000000000000000000 So we can conclude under BSD that |Ø(E)| = 4