A351666 Discriminants of imaginary quadratic fields with class number 28 (negated).

831, 935, 1095, 1311, 1335, 1364, 1455, 1479, 1496, 1623, 1703, 1711, 1855, 1976, 2024, 2055, 2120, 2127, 2324, 2359, 2431, 2455, 2564, 2607, 2616, 2703, 3224, 3272, 3396, 3419, 3487, 3535, 3572, 3576, 3608, 3624, 3731, 3848, 3995, 4040, 4183, 4279, 4344

Offset

1,1

Comments

Sequence contains 457 terms; largest is 126043.

The class groups associated to 174 of the above discriminants are isomorphic to C_28, and the remaining 283 have a class group isomorphic to C_14 X C_2.

Links

Andy Huchala, Table of n, a(n) for n = 1..457

Eric Weisstein's World of Mathematics, Class Number

Prog

(Sage)
ls = [(QuadraticField(-n, 'a').discriminant(), QuadraticField(-n, 'a').class_number()) for n in (0..10000) if is_fundamental_discriminant(-n) and not is_square(n)];
[-a[0] for a in ls if a[1] == 28]
(PARI) isok(n) = {isfundamental(-n) && quadclassunit(-n).no == 28}; \\ Michel Marcus, Mar 02 2022

Crossrefs

Cf. A006203, A013658, A014602, A014603, A046002-A046020, A046125, A056987, A351664.

Sequence in context: A252423 A252416 A125519 * A045070 A186956 A252561

Adjacent sequences: A351663 A351664 A351665 * A351667 A351668 A351669

Keyword

nonn,fini,full

Author

Andy Huchala, Feb 16 2022

Status

approved