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Search: id:A055484
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| A055484 |
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Number of unlabeled 3-element intersecting families (with not necessary distinct sets) of an n-element set. |
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+0
3
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| 1, 4, 14, 39, 96, 213, 437, 837, 1520, 2632, 4380, 7040, 10979, 16668, 24716, 35879, 51104, 71549, 98625, 134025, 179782, 238292, 312386, 405368, 521083, 663968, 839140, 1052439, 1310534, 1620985, 1992343, 2434229, 2957458, 3574108
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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V. Jovovic, G. Kilibarda, On the number of Boolean functions in the Post classes F^{mu}_8, Diskretnaya Matematika, 11 (1999), no. 4, 127-138 (translated in Discrete Mathematics and Applications, 9, (1999), no. 6).
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FORMULA
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G.f. : -x*(x^3-x^2-1)*(x^6+x^4+2*x^3+x^2+1)/((x^3-1)^2*(x^2-1)^2*(x-1)^4).
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CROSSREFS
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Cf. A053155 (labeled case), A005783, A002727, A051180.
Sequence in context: A114845 A064463 A130423 this_sequence A055279 A074083 A144141
Adjacent sequences: A055481 A055482 A055483 this_sequence A055485 A055486 A055487
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KEYWORD
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nonn
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AUTHOR
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Vladeta Jovovic, Goran Kilibarda (vladeta(AT)eunet.rs), Jul 03 2000
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Jul 04 2000
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