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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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2
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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; refs; listen; history; internal format)
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OFFSET
| 3,1
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REFERENCES
| 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
| 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
| Cf. A051180 (labeled case), A005783.
Sequence in context: A108484 A134507 A098813 * A000306 A100185 A129019
Adjacent sequences: A055482 A055483 A055484 * A055486 A055487 A055488
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KEYWORD
| nonn
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AUTHOR
| Vladeta Jovovic, Goran Kilibarda (vladeta(AT)eunet.rs), Jul 03 2000
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EXTENSIONS
| More terms from James A. Sellers (sellersj(AT)math.psu.edu), Jul 04 2000
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