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 A049414 #16 Jul 31 2021 02:15:32 %S A049414 1,3,54,3804,1022320,1065957628,4389587378792,72020744942708040, %T A049414 4721708591209396542528,1237892622263984613044109216, %U A049414 1298060581376190776821670648395840 %N A049414 Number of quasi-initially connected digraphs with n labeled nodes. %C A049414 We say that a node v of a digraph is a quasi-source iff for every other node u there exists directed path from u to v or from v to u. A digraph with at least one quasi-source is called quasi-initially connected. %H A049414 Sean A. Irvine, <a href="https://github.com/archmageirvine/joeis/blob/master/src/irvine/oeis/a049/A049414.java">Java program</a> (github) %H A049414 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. %F A049414 The recurrence formulas are too long to be presented here. %Y A049414 Cf. A003027, A003028, A003029, A003030. %Y A049414 Row sums of A057272. %K A049414 nonn %O A049414 1,2 %A A049414 _Vladeta Jovovic_, Goran Kilibarda