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 1-2 of 2 results.

A309162 Rank of elliptic curve y^2 = x * (x+1) * (x+n).

Original entry on oeis.org

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

Views

Author

Seiichi Manyama, Jul 15 2019

Keywords

Crossrefs

Programs

  • PARI
    {a(n) = ellanalyticrank(ellinit([0, n+1, 0, n, 0]))[1]}

A372543 Least k such that the rank of the elliptic curve y^2 = x^3 - k^2*x + 1 is n, or -1 if no such k exists.

Original entry on oeis.org

0, 1, 2, 4, 8, 17, 61, 347, 3778, 11416
Offset: 0

Views

Author

Jose Aranda, Jul 04 2024

Keywords

Comments

This family of curves quickly reaches a moderate value of rank with a relatively small parameter k.
By heuristic search (see links), a(10) <= 216493 and a(11) <= 1448203.

Crossrefs

Programs

  • PARI
    a(n,startAt=0)=for(k=startAt, oo, my(t=ellrank(ellinit([-k^2, +1]))); if(t[2]n, warning("k=",k," has rank in ",t[1..2]); next); if(t[1]n, error("Cannot determine if a(",n,") is ",k," or larger; rank is in ",t[1..2])); return(k)) \\ Charles R Greathouse IV, Jul 08 2024
    
  • PARI
    \\ See Aranda link.
Showing 1-2 of 2 results.