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 A058731 #18 Aug 29 2019 15:44:44 %S A058731 0,0,0,1,2,4,9,23,68,383,5249,232928,28872972 %N A058731 Number of nonisomorphic simple matroids of rank 3 on n unlabeled points. %H A058731 Mohamed Barakat, Reimer Behrends, Christopher Jefferson, Lukas Kühne, Martin Leuner, <a href="https://arxiv.org/abs/1907.01073">On the generation of rank 3 simple matroids with an application to Terao's freeness conjecture</a>, arXiv:1907.01073 [math.CO], 2019. %H A058731 Crapo, Henry H.; Rota, Gian-Carlo; <a href="/A002773/a002773.pdf">On the foundations of combinatorial theory. II. Combinatorial geometries</a>, Studies in Appl. Math. 49 1970 109-133. [Annotated scanned copy of pages 126 and 127 only] %H A058731 W. M. B. Dukes, <a href="http://www.stp.dias.ie/~dukes/matroid.html">Tables of matroids</a> %H A058731 W. M. B. Dukes, <a href="http://www.stp.dias.ie/~dukes/phd.html">Counting and Probability in Matroid Theory</a>, Ph.D. Thesis, Trinity College, Dublin, 2000. %H A058731 <a href="/index/Mat#matroid">Index entries for sequences related to matroids</a> %Y A058731 Equals A001200 - 1 (see that entry for further information). %Y A058731 A diagonal of A058730. %K A058731 nonn,nice,more %O A058731 0,5 %A A058731 _N. J. A. Sloane_, Dec 31 2000; May 28 2006 %E A058731 Definition corrected by _Gordon Royle_, Feb 13 2007