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 A054951 #23 Jan 14 2022 23:18:57
%S A054951 1,1,4,78,4960,1041872,704369984,1579641879248,12137443766888448,
%T A054951 328148810741254606592,31830752699315833628787200,
%U A054951 11234243165959817684710307801600,14576241398832991116522929933694031872,70075699209573863790264288901653500497274880
%N A054951 Number of unlabeled semi-strong digraphs on n nodes with mutually nonisomorphic components.
%C A054951 A digraph is semi-strong if all its weakly connected components are strongly connected. - _Andrew Howroyd_, Jan 14 2022
%D A054951 V. A. Liskovets, A contribution to the enumeration of strongly connected digraphs, Dokl. AN BSSR, 17 (1973), 1077-1080 (Russian), MR49#4849.
%H A054951 Andrew Howroyd, <a href="/A054951/b054951.txt">Table of n, a(n) for n = 1..50</a>
%H A054951 V. A. Liskovets, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL3/LISK/Derseq.html">Some easily derivable sequences</a>, J. Integer Sequences, 3 (2000), #00.2.2.
%F A054951 G.f.: 1 - Product_{n > 0} (1 - x^n)^A035512(n). - _Andrew Howroyd_, Sep 10 2018
%t A054951 m = 15;
%t A054951 A035512 = Cases[Import["https://oeis.org/A035512/b035512.txt", "Table"], {_, _}][[All, 2]];
%t A054951 gf = 1 - Product[(1 - x^n)^A035512[[n + 1]], {n, 1, m}];
%t A054951 CoefficientList[gf + O[x]^m , x] // Rest (* _Jean-François Alcover_, Aug 26 2019, after _Andrew Howroyd_ *)
%Y A054951 Cf. A035512, A049387, A054952, A054953, A054954.
%K A054951 nonn,easy
%O A054951 1,3
%A A054951 _N. J. A. Sloane_, May 24 2000
%E A054951 More terms from _Vladeta Jovovic_, Mar 11 2003
%E A054951 a(12)-a(14) from _Andrew Howroyd_, Sep 10 2018