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Discriminants of imaginary quadratic fields with class number 26 (negated).
16

%I #16 Mar 25 2022 09:16:01

%S 551,951,1247,1256,1735,1832,2651,2771,2792,2823,2839,2984,3092,3327,

%T 3368,3611,3736,3903,3992,4052,4207,4244,4376,4739,5123,5435,5524,

%U 5891,6059,6443,6515,6587,6676,6847,6891,6964,7156,8003,8339,8383,8408,8691,8743

%N Discriminants of imaginary quadratic fields with class number 26 (negated).

%C Sequence contains 190 terms; largest is 103027.

%C The class group of Q[sqrt(-d)] is isomorphic to C_26 for all d in this sequence.

%H Andy Huchala, <a href="/A351664/b351664.txt">Table of n, a(n) for n = 1..190</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/ClassNumber.html">Class Number.</a>

%o (Sage)

%o 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 [-a[0] for a in ls if a[1] == 26]

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

%K nonn,fini,full

%O 1,1

%A _Andy Huchala_, Feb 16 2022