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Search: id:A053153
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| A053153 |
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Number of 3-element intersecting families whose union is an n-element set. |
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+0
2
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| 0, 0, 13, 170, 1605, 13390, 104993, 794010, 5867245, 42681830, 307120473, 2192847250, 15570312485, 110116458270, 776528783953, 5464646634890, 38398786511325, 269529019274710, 1890415785439433, 13251574765596930
(list; graph; listen)
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OFFSET
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1,3
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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!*(7^n-3*5^n+3*4^n-4*3^n+3*2^n+2)
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CROSSREFS
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Cf. A051180.
Adjacent sequences: A053150 A053151 A053152 this_sequence A053154 A053155 A053156
Sequence in context: A020533 A067220 A057684 this_sequence A140455 A041314 A065544
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KEYWORD
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easy,nonn
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AUTHOR
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Vladeta Jovovic, Goran Kilibarda (vladeta(AT)Eunet.yu), Feb 28 2000
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Mar 01 2000
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