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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.

A351676 Discriminants of imaginary quadratic fields with class number 38 (negated).

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%I A351676 #11 Feb 16 2025 08:34:03
%S A351676 1199,1535,1671,2031,3047,3415,4916,5127,5528,6423,6548,6559,6927,
%T A351676 7016,7091,7135,7444,8276,8315,8651,8939,8983,9179,9487,9524,9659,
%U A351676 9727,9908,10216,10715,10779,10984,11432,11463,11507,11915,12779,12904,13667,14099,14164
%N A351676 Discriminants of imaginary quadratic fields with class number 38 (negated).
%C A351676 Sequence contains 237 terms; largest is 289963.
%C A351676 The class group of Q[sqrt(-d)] is isomorphic to C_38 for all d in this sequence.
%H A351676 Andy Huchala, <a href="/A351676/b351676.txt">Table of n, a(n) for n = 1..237</a>
%H A351676 Mark Watkins, <a href="https://doi.org/10.1090/S0025-5718-03-01517-5">Class numbers of imaginary quadratic fields</a>, Mathematics of Computation, 73, pp. 907-938.
%H A351676 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ClassNumber.html">Class Number</a>
%o A351676 (Sage)
%o A351676 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)];
%o A351676 [-a[0] for a in ls if a[1] == 38]
%Y A351676 Cf. A006203, A013658, A014602, A014603, A046002-A046020, A046125, A056987, A351664-A351680.
%K A351676 nonn,fini,full
%O A351676 1,1
%A A351676 _Andy Huchala_, Mar 27 2022