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A003029
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Number of unilaterally connected digraphs with n labeled nodes.
(Formerly M3156)
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6
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1, 3, 48, 3400, 955860, 1034141596, 4340689156440, 71756043154026904, 4716284688998245793376, 1237457313794197125403483936, 1297922676419612772784598299454784, 5444329780242560941321703550018388707904, 91342929096228825123968637168641318872709897472
(list;
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listen;
history;
text;
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OFFSET
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1,2
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REFERENCES
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V. Jovovic, G. Kilibarda, Enumeration of labeled initially-finally connected digraphs, Scientific review, Serbian Scientific Society, 19-20 (1996), 237-247.
R. W. Robinson, Counting labeled acyclic digraphs, pp. 239-273 of F. Harary, editor, New Directions in the Theory of Graphs. Academic Press, NY, 1973.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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Andrew Howroyd, Table of n, a(n) for n = 1..50
V. Jovovic and G. Kilibarda, Enumeration of labeled quasi-initially connected digraphs, Discrete Math., 224 (2000), 151-163.
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PROG
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(PARI) Unilaterally(12) \\ See A057275. - Andrew Howroyd, Jan 19 2022
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CROSSREFS
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The unlabeled version is A003088.
Row sums of A057275.
Cf. A003027, A003028, A003030, A049524, A049414.
Sequence in context: A356612 A295813 A326217 * A049524 A270748 A322363
Adjacent sequences: A003026 A003027 A003028 * A003030 A003031 A003032
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KEYWORD
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nonn,nice,easy
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AUTHOR
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N. J. A. Sloane
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EXTENSIONS
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Corrected and extended by Vladeta Jovovic, Goran Kilibarda
Terms a(12) and beyond from Andrew Howroyd, Jan 11 2022
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STATUS
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approved
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