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 A055109 #15 May 25 2024 16:13:27 %S A055109 26,29,38,53,61,87,106,109,118,157,202,214,247,262,277,298,339,358, %T A055109 397,411,451,515,707,771,835,843,1059,1099,1147,1203,1219,1267,1315, %U A055109 1347,1363,1563,1603,1843,1915,1963,2227,2283,2443,2515,2563,2787 %N A055109 Numbers k such that Q(sqrt(-k)) has class number 6. %H A055109 Jinyuan Wang, <a href="/A055109/b055109.txt">Table of n, a(n) for n = 1..51</a> %H A055109 <a href="/index/Qua#quadfield">Index entries for sequences related to quadratic fields</a> %t A055109 Select[Range[10000], MoebiusMu[#] != 0 && NumberFieldClassNumber[Sqrt[-#]] == 6 &] (* _Jinyuan Wang_, Mar 08 2020 *) %o A055109 (PARI) \\ See A005847. %Y A055109 See A003173, A005847, A006203, A046085, A046002, A055109, A046004, A055110, A046006, A055111 for class numbers 1 through 10. %K A055109 nonn,fini,full %O A055109 1,1 %A A055109 _N. J. A. Sloane_, Jun 16 2000