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Search: id:A055485
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| A055485 |
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Number of unlabeled 3-element intersecting families (with distinct sets) of an n-element set. |
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+0
3
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| 4, 19, 61, 157, 353, 717, 1355, 2412, 4094, 6676, 10524, 16108, 24036, 35063, 50135, 70409, 97295, 132485, 178011, 236268, 310086, 402768, 518158, 660692, 835486, 1048379, 1306039, 1616025, 1986887, 2428245, 2950913, 3566968, 4289896
(list; graph; listen)
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OFFSET
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3,1
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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^3*(x^8+x^7-3*x^6-x^5+x^4+3*x^3-x^2-3*x-4)/((x^3-1)^2*(x^2-1)^2*(x-1)^4).
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CROSSREFS
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Cf. A051180 (labeled case), A005783.
Sequence in context: A108484 A134507 A098813 this_sequence A000306 A100185 A129019
Adjacent sequences: A055482 A055483 A055484 this_sequence A055486 A055487 A055488
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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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