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A066019
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Triangle of covering numbers T(n,k) = C(n,k,k-2), n >= 3, 3 <= k <= n.
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0
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1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 3, 5, 5, 5, 1, 3, 6, 8, 7, 6, 1, 3, 8, 12, 12, 9, 7, 1, 4, 9, 17, 20, 20, 12, 8, 1
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OFFSET
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3,2
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COMMENTS
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C(v,k,t) is the smallest number of k-subsets of an n-set such that every t-subset is contained in at least one of the k-subsets.
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REFERENCES
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CRC Handbook of Combinatorial Designs, 1996, p. 263.
W. H. Mills and R. C. Mullin, Coverings and packings, pp. 371-399 of Jeffrey H. Dinitz and D. R. Stinson, editors, Contemporary Design Theory, Wiley, 1992.
Kari J. Nurmela and Patric R. J. Östergård, Covering t-sets with (t+2)-sets. Proceedings of the Conference on Optimal Discrete Structures and Algorithms-ODSA '97 (Rostock).
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LINKS
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EXAMPLE
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Triangle begins:
1;
2 1;
2 3 1;
2 3 4 1;
3 5 5 5 1;
...
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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