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.
%I A351679 #11 Feb 16 2025 08:34:03 %S A351679 1151,2551,2719,3079,3319,3511,6143,9319,9467,10499,10903,11047,11483, %T A351679 11719,11987,12227,12611,13567,14051,14411,14887,14983,16067,16187, %U A351679 19763,20407,20771,21487,22651,24971,25171,26891,26987,27739,28547,29059,29251,30859 %N A351679 Discriminants of imaginary quadratic fields with class number 41 (negated). %C A351679 Sequence contains 109 terms; largest is 296587. %C A351679 The class group of Q[sqrt(-d)] is isomorphic to C_41 for all d in this sequence. %H A351679 Andy Huchala, <a href="/A351679/b351679.txt">Table of n, a(n) for n = 1..109</a> %H A351679 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 A351679 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ClassNumber.html">Class Number</a> %o A351679 (Sage) %o A351679 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 A351679 [-a[0] for a in ls if a[1] == 41] %Y A351679 Cf. A006203, A013658, A014602, A014603, A046002-A046020, A046125, A056987, A351664-A351680. %K A351679 nonn,fini,full %O A351679 1,1 %A A351679 _Andy Huchala_, Mar 28 2022