A060838 Rank of elliptic curve x^3 + y^3 = n.

0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 2, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 2, 1, 0, 1, 1, 1, 0, 2, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 0, 2, 0, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1

Offset: 1

Author

Noam Katz (noamkj(AT)hotmail.com), May 02 2001

Keywords

• nonn
• nice

Comments

The elliptic curve X^3 + Y^3 = D*Z^3 where D is a rational integer has a birationally equivalent form y^2*z = x^3 - 2^4*3^3*D^2*z^3 where x = 2^2*3*D*Z, y = 2^2*3^3*D*(Y - X), z = X + Y (see p. 123 of Stephens). Taking z = 1 and 2^2*3^3 = 432 yields y^2 = x^3 - 432*D^2, which is the Weierstrass form of the elliptic curve used by John Voight in the Magma program below. - Ralf Steiner, Nov 11 2017

Zagier and Kramarz studied the analytic rank of the curve E: x^3 + y^3 = m, where m is cubefree. They computed L(E,1) for 0 < m <= 70000 and also L'(E,1) if the sign of the functional equation for L(E,1) was negative. In the second case the range was only 0 < m <= 20000. - Attila Pethő, Posting to the Number Theory List, Nov 11 2017

Links

• John Voight and Joseph L. Wetherell, Table of n, a(n) for n = 1..10000
• Nakao Hisayasu, Tables of the rank and rational points for the elliptic curve x^3 + y^3 = n for n cubefree, 1<=n<=200 (text in Japanese)
• Nakao Hisayasu, Tables of the rank and rational points for the elliptic curve x^3 + y^3 = n for n cubefree, 201<=n<=500 (text in Japanese)
• Nakao Hisayasu, Tables of the rank and rational points for the elliptic curve x^3 + y^3 = n for n cubefree, 501<=n<=1000 (text in Japanese)
• Nakao Hisayasu, Tables of the rank and rational points for the elliptic curve x^3 + y^3 = n for n cubefree, 1001<=n<=1500 (text in Japanese)
• Nakao Hisayasu, Tables of the rank and rational points for the elliptic curve x^3 + y^3 = n for n cubefree, 1501<=n<=2000 (text in Japanese)
• Nakao Hisayasu, Tables of the rank and rational points for the elliptic curve x^3 + y^3 = n for n cubefree, 2001<=n<=2500 (text in Japanese)
• ...
• Nakao Hisayasu, Tables of the rank and rational points for the elliptic curve x^3 + y^3 = n for n cubefree, 8501<=n<=9000 (text in Japanese)
• Nakao Hisayasu, Tables of the rank and rational points for the elliptic curve x^3 + y^3 = n for n cubefree, 9001<=n<=9500 (text in Japanese)
• Nakao Hisayasu, Tables of the rank and rational points for the elliptic curve x^3 + y^3 = n for n cubefree, 9501<=n<=10000 (text in Japanese)
• N. M. Stephens, The Diophantine equation X^3 + Y^3 = D Z^3 and the conjectures of Birch and Swinnerton-Dyer, J. Reine Angew. Math. 231 (1968), 121-162.
• D. Zagier and G. Kramarz, Numerical investigations related to the L-series of certain elliptic curves, J. Indian Math. Soc. 52 (1987), 51-60 (the Ramanujan Centenary volume).

Crossrefs

Cf. A060748 (positions of records in this sequence), A060950.

Programs

Magma

seq := [];
M := 10000;
for m := 1 to M do
E := EllipticCurve([0,-432*m^2]);
Append(~seq, Rank(E));
end for;
seq;
// John Voight, Nov 02 2017

PARI

{a(n) = ellanalyticrank(ellinit([0, 0, 0, 0, -432*n^2]))[1]} \\ Seiichi Manyama, Aug 25 2019

Extensions

Many thanks to Andrew V. Sutherland, John Voight, and Joseph L. Wetherell, who all responded to my request for additional terms for this sequence. - N. J. A. Sloane, Nov 01 2017