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A005786
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Number of 6-covers of an n-set.
(Formerly M4244)
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9
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1, 6, 43, 336, 2864, 25326, 223034, 1890123, 15115098, 112980937, 787320629, 5121184083, 31188412225, 178517111561, 964196387369, 4933278065881, 23997707450765, 111358094980387, 494444748602595, 2106504840061571
(list;
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refs;
listen;
history;
text;
internal format)
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OFFSET
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0,2
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REFERENCES
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R. J. Clarke, Covering a set by subsets, Discrete Math., 81 (1990), 147-152.
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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Table of n, a(n) for n=0..19.
Vladeta Jovovic, Binary matrices up to row and column permutations
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CROSSREFS
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Cf. A002620, A005783, A005784, A005785, A055066.
Sequence in context: A025594 A098665 A153397 * A071541 A146966 A240653
Adjacent sequences: A005783 A005784 A005785 * A005787 A005788 A005789
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane.
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EXTENSIONS
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More terms from Vladeta Jovovic, Jun 12 2000
a(0)=1 prepended by Alois P. Heinz, Aug 08 2022
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STATUS
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approved
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