cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-8 of 8 results.

A031507 a(n) = smallest k>0 such that the elliptic curve y^2 = x^3 + k has rank n, or -1 if no such k exists.

Original entry on oeis.org

1, 2, 15, 113, 2089, 66265, 1358556
Offset: 0

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Author

Keywords

Comments

See A031508 for the smallest negative k. - Artur Jasinski, Nov 21 2011
See A060950 for the rank of y^2 = x^3 + n. - Jonathan Sondow, Sep 10 2013
Gebel, Pethö, & Zimmer: "One experimental observation derived from the tables is that the rank r of Mordell's curves grows according to r = O(log |k|/|log log |k||^(2/3))." Hence this fit suggests a(n) >> exp(n (log n)^(1/3)) where >> is the Vinogradov symbol. - Charles R Greathouse IV, Sep 10 2013
The curves for k and -27*k are isogenous (as Noam Elkies points out---see Womack), so they have the same rank. - Jonathan Sondow, Sep 10 2013
Womack (2003) gives further upper bounds: a(7) <= 47550317, a(8) <= 1632201497, a(9) <= 185418133372, a(10) <= 68513487607153. - M. F. Hasler, Jul 01 2024
The three questions for arbitrary k, positive k, and negative k are not very far from each other because the curves for k and -27k are related by a 3-isogeny and therefore have the same rank. It would be most natural to ask for the minimal |k| for k of either sign [see A373795]. - Noam D. Elkies, Jul 02 2024
a(16) <= 1160221354461565256631205207888 (Elkies, ANTS-XVI, 2024). The same article also establishes the existence of a value of k which has rank >= 17. - N. J. A. Sloane, Jul 05 2024

Examples

			a(12) <= 27*A031508(12) <= 27*6533891544658786928 = 176415071705787247056 (from Quer 1987 and Womack). - _Jonathan Sondow_, Sep 10 2013
		

References

  • Noam D. Elkies, Rank of an elliptic curve and 3-rank of a quadratic field via the Burgess bounds, 2024 Algorithmic Number Theory Symposium, ANTS-XVI, MIT, July 2024.

Crossrefs

Programs

  • PARI
    {A031507(n)=for(k=1, oo, ellrank(ellinit([0, k]))[1]==n && return(k))} \\ Use ellanalyticrank() for PARI version < 2.14. - M. F. Hasler, Jul 01 2024

Formula

a(n) <= 27*A031508(n) and A031508(n) <= 27*a(n). - Jonathan Sondow, Sep 10 2013

Extensions

Definition clarified by Jonathan Sondow, Oct 26 2013
Escape clause added to definition by N. J. A. Sloane, Jun 29 2024, because, as John Cremona reminds me, it is not known if k always exists.

A060951 Rank of elliptic curve y^2 = x^3 - n.

Original entry on oeis.org

0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 2, 0, 1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 2, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 2, 1, 0, 0, 1, 1, 1, 0, 2, 1, 1, 1, 1, 0, 2, 1, 1, 1, 1, 1, 1, 1, 2, 0, 1, 0, 1, 1, 2, 0, 0, 0, 1, 1, 0, 1, 1, 2, 0, 0, 1, 0, 1, 0, 2, 1, 1, 0, 1, 0, 2
Offset: 1

Views

Author

N. J. A. Sloane, May 10 2001

Keywords

Comments

The curves for n and -27*n are isogenous (as Noam Elkies points out--see Womack), so they have the same rank. - Jonathan Sondow, Sep 10 2013

Examples

			a(1) = A060950(27) = a(729) = 0. - _Jonathan Sondow_, Sep 10 2013
		

Crossrefs

Cf. A081120 (number of integral solutions to Mordell's equation y^2 = x^3 - n).

Programs

  • PARI
    {a(n) = if( n<1, 0, length( ellgenerators( ellinit( [ 0, 0, 0, 0, -n], 1))))} /* Michael Somos, Mar 17 2011 */
    
  • PARI
    apply( {A060951(n)=ellrank(ellinit([0,-n]))[1]}, [1..99]) \\ For version < 2.14, use ellanalyticrank(...). - M. F. Hasler, Jul 01 2024

Formula

a(n) = A060950(27*n) and A060950(n) = a(27*n), so a(n) = a(729*n). - Jonathan Sondow, Sep 10 2013

Extensions

Corrected Apr 08 2005 at the suggestion of James R. Buddenhagen. There were errors caused by the fact that Mishima lists each curve of rank two twice, once for each generator.

A031508 a(n) = smallest k > 0 such that the elliptic curve y^2 = x^3 - k has rank n, or -1 if no such k exists.

Original entry on oeis.org

1, 2, 11, 174, 2351, 28279, 975379
Offset: 0

Views

Author

Keywords

Comments

See A031507 for the smallest k>0 such that the elliptic curve y^2 = x^3 + k has rank n. - Jonathan Sondow, Sep 06 2013
See A060951 for the rank of y^2 = x^3 - n. - Jonathan Sondow, Sep 10 2013
Gebel, Pethö, & Zimmer: "One experimental observation derived from the tables is that the rank r of Mordell's curves grows according to r = O(log |k|/|log log |k||^(2/3))." Hence this fit suggests a(n) >> exp(n (log n)^(1/3)) where >> is the Vinogradov symbol. - Charles R Greathouse IV, Sep 10 2013
a(7) <= 56877643. a(8) <= 2520963512. a(9) <= 463066403167. a(10) <= 56736325657288. a(11) <= 46111487743732324. a(12) <= 6533891544658786928. See Table 3.3 in [Womack 2003]. - Jose Aranda, Jun 30 2024
The three questions for arbitrary k, positive k, and negative k are not very far from each other because the curves for k and -27k are related by a 3-isogeny and therefore have the same rank. It would be most natural to ask for the minimal |k| for k of either sign [see A373795]. - Noam D. Elkies, Jul 02 2024
a(16) <= 1160221354461565256631205207888 (Elkies, ANTS-XVI, 2024). The same article also establishes the existence of a value of k which has rank >= 17. - N. J. A. Sloane, Jul 05 2024

Examples

			From _M. F. Hasler_, Jul 01 2024: (Start)
Sequence A060951 = (0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 2, 0, 1, 0, 1, 0, 0, 1, ...) gives the analytic rank of the elliptic curve y^2 = x^3 - k for k = 1, 2, 3, ...
We can see that:
  - the smallest k that gives rank 0 is k = 1 = a(0);
  - the smallest k that gives rank 1 is k = 2 = a(1);
  - the smallest k that gives rank 2 is k = 11 = a(2); etc. (End)
		

References

  • Noam D. Elkies, Rank of an elliptic curve and 3-rank of a quadratic field via the Burgess bounds, 2024 Algorithmic Number Theory Symposium, ANTS-XVI, MIT, July 2024.

Crossrefs

Programs

  • PARI
    {a(n) = my(k=1); while(ellanalyticrank(ellinit([0, 0, 0, 0, -k]))[1]<>n, k++); k} \\ Seiichi Manyama, Aug 24 2019
    
  • PARI
    {A031508(n)=for(k=1,oo, ellrank(ellinit([0, -k]))[1]==n && return(k))} \\ M. F. Hasler, Jul 01 2024

Formula

a(n) = min { k >= 1 | A060951(k) == n }. - M. F. Hasler, Jul 01 2024

Extensions

Definition clarified by Jonathan Sondow, Oct 26 2013.
Escape clause added to definition by N. J. A. Sloane, Jun 29 2024, because, as John Cremona reminds me, it is not known if k always exists.

A076329 Numbers k for which rank of the elliptic curve y^2=x^3+k*x is 2.

Original entry on oeis.org

14, 33, 34, 39, 46, 55, 63, 65, 66, 68, 73, 89, 94, 99, 105, 113, 114, 129, 138, 145, 150, 154, 155, 158, 178, 183, 185, 201, 203, 206, 209, 219, 224, 226, 233, 238, 254, 258, 260, 273, 274, 281, 289, 295, 299, 308, 310, 333, 334, 337, 345, 353, 354, 360, 385, 386, 388
Offset: 1

Views

Author

N. J. A. Sloane, Nov 06 2002

Keywords

References

  • D. S. Jandu, Elliptic Curve, Infinite Bandwidth Publishing, N. Hollywood CA 2007.
  • D. S. Jandu, Birch And Swinnerton Dyer Conjecture, Infinite Bandwidth Publishing, N. Hollywood CA 2007.
  • D. Zagier & G. Harder, "La conjecture de Birch et Swinnerton-Dyer" in Les Dossiers de La Recherche, pp. 48-53 No. 20 August-October 2005 Paris.

Crossrefs

Programs

  • PARI
    for(k=1, 1e3, if(ellanalyticrank(ellinit([0, 0, 0, k, 0]))[1]==2, print1(k", "))) \\ Seiichi Manyama, Jul 07 2019

Extensions

More terms added by Seiichi Manyama, Jul 07 2019

A179136 Parameters n for which the elliptic curve y^2=x^3-n has rank 3.

Original entry on oeis.org

174, 307, 362, 431, 503, 516, 706, 713, 741, 755, 804, 984, 1048, 1075, 1173, 1187, 1192, 1208, 1236, 1259, 1315, 1356, 1439, 1478, 1588, 1607, 1668, 1712, 1724, 1727, 1763, 1777, 1812, 1902, 1951, 1966, 1999, 2001, 2036, 2071, 2181, 2188, 2198, 2219
Offset: 1

Views

Author

Artur Jasinski, Jun 30 2010

Keywords

Crossrefs

Cf. A002150 (rank 0), A002152 (rank 1), A002154 (rank 2), A031508, A179137 (rank 4).

A179137 Parameters n for which the elliptic curve y^2=x^3-n has rank 4.

Original entry on oeis.org

2351, 3896, 4799, 4827, 5417, 5835, 6691, 6843, 9748, 9967, 10723, 11559, 12163, 12394, 12891, 13971, 14188, 14907, 15049, 15544
Offset: 1

Views

Author

Artur Jasinski, Jun 30 2010

Keywords

Crossrefs

Cf. A002150 (rank 0), A002152 (rank 1), A002154 (rank 2), A179136 (rank 3).
Cf. A031508.

Programs

  • PARI
    for(k=1, 1e4, if(ellanalyticrank(ellinit([0, 0, 0, 0, -k]))[1]==4, print1(k", "))) \\ Seiichi Manyama, Jul 07 2019

Extensions

a(11)-a(20) from Seiichi Manyama, Jul 07 2019

A076330 Elliptic curves (see reference for precise definition).

Original entry on oeis.org

17, 41, 57, 62, 82, 97, 117, 137, 142, 146, 161, 177, 193, 194, 392, 452, 792
Offset: 1

Views

Author

N. J. A. Sloane, Nov 06 2002

Keywords

Crossrefs

Cf. A002150-A002159. Subsequence of A002158.

A076331 Elliptic curves (see reference for precise definition).

Original entry on oeis.org

136, 584, 712, 776
Offset: 1

Views

Author

N. J. A. Sloane, Nov 06 2002

Keywords

Crossrefs

Cf. A002150-A002159. Subsequence of A002159.
Showing 1-8 of 8 results.