Burkhardt quartic specialization b = -1, c = -a - d with (a,d) = (3,12), using the auxiliary quartic rational point t = 16179/2645, w = 25201350720/279841. The resulting cubesum curve is u^3 + v^3 = 245370294 after rational cube scaling. PARI/GP 2.17.4 ellrank bounds [6,6].
jesper-petersen ·