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 A051977 #7 Sep 21 2021 06:08:50 %S A051977 247,295,355,366,385,386,426,535,609,767,802,815,851,969,995,1027, %T A051977 1113,1162,1207,1343,1353,1355,1358,1535,1538,1703,1717,1799,1910, %U A051977 1946,2018,2047,2054,2105,2231,2318,2327,2334,2365,2438,2507,2735 %N A051977 Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 12. %D A051977 R. A. Mollin, Quadratics, CRC Press, 1996, Appendix A, Table A3. %H A051977 Georg Fischer, <a href="/A051977/b051977.txt">Table of n, a(n) for n = 1..102</a> %Y A051977 Cf. A051966-A051989. %K A051977 nonn,fini,full %O A051977 1,1 %A A051977 _N. J. A. Sloane_, Jan 04 2000