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A003467
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Number of minimal covers of an n-set.
(Formerly M3951)
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0
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5, 28, 190, 1340, 9065, 57512, 344316, 1966440, 10813935, 57672340, 299893594, 1526727748, 7633634645, 37580965520, 182536112120, 876173330832
(list; graph; refs; listen; history; internal format)
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OFFSET
| 3,1
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REFERENCES
| Hearne and Wagner, Minimal covers of finite sets, Discr. Math. 5 (1973), 247-251.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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FORMULA
| G.f.: 1 + ( 1 - 4 x )^-4 + 3 ( 1 - x )^-4.
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CROSSREFS
| Sequence in context: A070779 A189487 A024065 * A064898 A151500 A107875
Adjacent sequences: A003464 A003465 A003466 * A003468 A003469 A003470
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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