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 A361560 Number of labeled digraphs on [n] all of whose strongly connected components are complete digraphs. 1
 1, 1, 4, 47, 1471, 115042, 21591817, 9455689609, 9464951556046, 21316993121024757, 106689322228222150243, 1174731578884501228621956, 28221161668500867009724237123, 1468937207982284446757761131062629, 164682046577167683717133576752582349216, 39562388056404531283767850863430043742371123 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Table of n, a(n) for n=0..15. E. de Panafieu and S. Dovgal, Symbolic method and directed graph enumeration, arXiv:1903.09454 [math.CO], 2019. R. W. Robinson, Counting digraphs with restrictions on the strong components, Combinatorics and Graph Theory '95 (T.-H. Ku, ed.), World Scientific, Singapore (1995), 343-354. Wikipedia, Strongly connected component MATHEMATICA nn = 15; B[n_] := n! 2^Binomial[n, 2]; a[x_] := Exp[x] - 1; Table[B[n], {n, 0, nn}] CoefficientList[Series[1/Normal[Series[Exp[-(Exp[x] - 1)], {x, 0, nn}]] /. Table[x^i -> z^i/2^Binomial[i, 2], {i, 0, nn}], {z, 0, nn}], z] CROSSREFS Cf. A011266 (all strong components are cycles), A361527, A003024 (all strong components are singletons). Sequence in context: A006438 A251665 A210828 * A333247 A330039 A141040 Adjacent sequences: A361557 A361558 A361559 * A361561 A361562 A361563 KEYWORD nonn AUTHOR Geoffrey Critzer, Mar 15 2023 STATUS approved

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Last modified December 8 17:58 EST 2023. Contains 367680 sequences. (Running on oeis4.)