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 A139627 #14 Jan 14 2022 19:45:28 %S A139627 1,1,2,4,12,37,162,738,3928,22436,138716,911529,6339770,46336941, %T A139627 354453138,2826472249,23423053967,201179882629,1786791372857, %U A139627 16377359709120,154644691266520,1502016160624186,14985219655673207,153377735526218010,1608741204839374373 %N A139627 Number of strongly connected directed multigraphs with loops allowed and with n arcs. %C A139627 The term a(0)=1 can be interpreted as either a singleton vertex or the graph with no vertices. - _Andrew Howroyd_, Jan 14 2022 %H A139627 Andrew Howroyd, <a href="/A139627/b139627.txt">Table of n, a(n) for n = 0..40</a> %o A139627 (PARI) \\ See PARI link in A350489 for program code. %o A139627 A139627seq(20) \\ _Andrew Howroyd_, Jan 14 2022 %Y A139627 Row sums of A139622. %Y A139627 Cf. A052171, A350489, A350752. %K A139627 nonn %O A139627 0,3 %A A139627 _Benoit Jubin_, May 01 2008 %E A139627 3 more terms from _R. J. Mathar_, Aug 04 2017 %E A139627 Terms a(7) and beyond from _Andrew Howroyd_, Jan 14 2022