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 A218157 #6 Feb 16 2025 08:33:18 %S A218157 577,1009,1601,1761,2029,2913,4229,4348,5176,5273,5417,7736,8097,8661, %T A218157 8773,9004,9029,9049,9101,9208,9289,9868,10117,10313,10357,10713, %U A218157 10957,11021,11053,11269,11537,11621,12497,12977,13049,13313,13701,14201,15277,15809 %N A218157 Fundamental discriminants of real quadratic number fields with class number 7. %H A218157 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ClassNumber.html">Class Number</a> %H A218157 <a href="/index/Qua#quadfield">Index entries for sequences related to quadratic fields</a> %t A218157 Select[Range[15809], NumberFieldDiscriminant@Sqrt[#] == # && NumberFieldClassNumber@Sqrt[#] == 7 &] %Y A218157 Cf. A003656, A094619, A094612-A094614, A218156, A218158-A218160. %K A218157 nonn %O A218157 1,1 %A A218157 _Arkadiusz Wesolowski_, Oct 22 2012