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