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 A005331 M1531 #29 Jul 09 2025 17:32:30
%S A005331 1,2,5,20,179,4082,218225,25316720,6135834479,3047003143022,
%T A005331 3067545380897645,6223557209578656620,25360384878802358268779,
%U A005331 207167485813280961035481962,3389045635023473628621934703465,110960673463328354866093662279119720,7268699514166911556909103208203294815079
%N A005331 Certain subgraphs of a directed graph (binomial transform of A005321).
%D A005331 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A005331 Michael De Vlieger, <a href="/A005331/b005331.txt">Table of n, a(n) for n = 0..81</a>
%H A005331 E. Andresen and K. Kjeldsen, <a href="http://dx.doi.org/10.1016/0012-365X(76)90054-6">On certain subgraphs of a complete transitively directed graph</a>, Discrete Math. 14 (1976), no. 2, 103-119.
%H A005331 Hsien-Kuei Hwang, Emma Yu Jin, and Michael J. Schlosser, <a href="https://arxiv.org/abs/2012.13570">Asymptotics and statistics on Fishburn Matrices: dimension distribution and a conjecture of Stoimenow</a>, arXiv:2012.13570 [math.CO], 2020.
%H A005331 N. J. A. Sloane, <a href="/transforms.txt">Transforms</a>
%F A005331 a(n) = Sum_{j=0..n} binomial(n,j)*A005321(j).
%t A005331 Block[{nn = 16, s}, s = CoefficientList[Series[Sum[x^n*Product[(2^i - 1)/(1 + (2^i - 1)*x), {i, n}], {n, 0, #}], {x, 0, #}], x] &@ nn; Array[Sum[Binomial[#, j] s[[j + 1]], {j, 0, #}] &, nn + 1, 0]] (* _Michael De Vlieger_, Apr 13 2021, after _Jean-François Alcover_ at A005321 *)
%K A005331 nonn
%O A005331 0,2
%A A005331 _N. J. A. Sloane_
%E A005331 More terms from _Max Alekseyev_, May 04 2010
%E A005331 a(15)-a(16) from _Michael De Vlieger_, Apr 13 2021