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 A051993 #8 Sep 21 2021 15:46:48 %S A051993 3,4,5,1,6,2,1,8,3,2,2,1,11,12,13,1,14,2,1,5,3,16,17,6,19,4,1,22,22, %T A051993 23,2,2,10,2,1,31,34,34,2,1,5,7,36,37,2,1,13,8,8,1,14,9,2,46,47,16,3, %U A051993 4,56,3,2,58,20,12,2,3,2,23,10,2,24,73,5,4,2,16,2,4,8,8,19,98,20,2,2,4,24,11,122,4,4,142,26,68,242,278,22,32 %N A051993 Consider real quadratic fields of ERD-type with class groups of exponent 2 and discriminants of the form D = r^2*k^2+k, k odd; sequence gives values of r. %D A051993 R. A. Mollin, Quadratics, CRC Press, 1996, Appendix A, Table A4(1), column r. %Y A051993 Cf. A051990, A051991, A051992, A051994, A051995, A051996, A051997, A051998. %K A051993 nonn,fini,full %O A051993 1,1 %A A051993 _N. J. A. Sloane_, Jan 04 2000 %E A051993 a(83) and following from _Georg Fischer_, Sep 21 2021