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.

A046004 Discriminants of imaginary quadratic fields with class number 7 (negated).

Original entry on oeis.org

71, 151, 223, 251, 463, 467, 487, 587, 811, 827, 859, 1163, 1171, 1483, 1523, 1627, 1787, 1987, 2011, 2083, 2179, 2251, 2467, 2707, 3019, 3067, 3187, 3907, 4603, 5107, 5923
Offset: 1

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Programs

  • Mathematica
    Union[(-NumberFieldDiscriminant[Sqrt[-#]] &) /@ Select[Range[6000], NumberFieldClassNumber[Sqrt[-#]] == 7 &]] (* Jean-François Alcover, Jun 27 2012 *)
  • PARI
    ok(n)={isfundamental(-n) && quadclassunit(-n).no == 7};
    for(n=1, 6000, if(ok(n)==1, print1(n, ", "))) \\ G. C. Greubel, Mar 01 2019
    
  • Sage
    [n for n in (1..6000) if is_fundamental_discriminant(-n) and QuadraticField(-n, 'a').class_number()==7] # G. C. Greubel, Mar 01 2019