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 A049512 #15 Aug 02 2021 02:29:02 %S A049512 1,2,13,197,9312,1528634,880277970 %N A049512 Number of quasi-initially connected digraphs on n unlabeled nodes. %C A049512 From _Sean A. Irvine_, Aug 01 2021: (Start) %C A049512 A quasi-initially connected digraph is a digraph containing at least one vertex v such that every vertex u in the graph can either be reached from v or v can be reached from u (while obeying the directions on the edges). %C A049512 There is no known formula. (End) %H A049512 Sean A. Irvine, <a href="https://github.com/archmageirvine/joeis/blob/master/src/irvine/oeis/a049/A049512.java">Java program</a> (github) %H A049512 V. Jovovic and G. Kilibarda, <a href="http://dx.doi.org/10.1016/S0012-365X(00)00112-6">Enumeration of labeled quasi-initially connected digraphs</a>, Discrete Math., 224 (2000), 151-163. %Y A049512 Cf. A049414, A003085, A035512, A003088, A051421. %K A049512 hard,more,nonn %O A049512 1,2 %A A049512 _Vladeta Jovovic_, Goran Kilibarda %E A049512 a(6)-a(7) from _Sean A. Irvine_, Aug 01 2021