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 A001985 M2669 N1068 #17 Feb 04 2022 00:39:48 %S A001985 3,7,19,25,51,109,153,213,289,1121,1121,1121,3997,7457,12017,12719, %T A001985 20299,24503,24503,25817,25817,128755,128755,219207,456929,456929, %U A001985 761619,883537 %N A001985 Class numbers of quadratic fields. %D A001985 D. H. Lehmer, E. Lehmer and D. Shanks, Integer sequences having prescribed quadratic character, Math. Comp., 24 (1970), 433-451. %D A001985 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). %D A001985 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A001985 D. H. Lehmer, E. Lehmer and D. Shanks, <a href="/A002189/a002189.pdf">Integer sequences having prescribed quadratic character</a>, Math. Comp., 24 (1970), 433-451 [Annotated scanned copy] %H A001985 <a href="/index/Qua#quadfield">Index entries for sequences related to quadratic fields</a> %K A001985 nonn,more %O A001985 3,1 %A A001985 _N. J. A. Sloane_