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Search: id:A051180
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| A051180 |
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Number of 3-element intersecting families of an n-element set. |
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+0
19
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| 0, 0, 0, 13, 222, 2585, 25830, 238833, 2111382, 18142585, 152937510, 1271964353, 10476007542, 85662034185, 696700867590, 5643519669073, 45575393343702, 367206720319385, 2953481502692070, 23723872215168993, 190372457332919862
(list; graph; listen)
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OFFSET
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0,4
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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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1/3!(8^n-3*6^n+3*5^n-4*4^n+3*3^n+2*2^n-2)
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MAPLE
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seq(1/3!*(8^n-3*6^n+3*5^n-4*4^n+3*3^n+2*2^n-2), n=0..40);
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CROSSREFS
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Cf. A036239, A051181-A051185.
Sequence in context: A086147 A015253 A051621 this_sequence A143832 A140841 A062127
Adjacent sequences: A051177 A051178 A051179 this_sequence A051181 A051182 A051183
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KEYWORD
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nonn,easy
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AUTHOR
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Vladeta Jovovic, Goran Kilibarda (vladeta(AT)eunet.rs)
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EXTENSIONS
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More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Mar 25 2002
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