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A066040 Triangle of covering numbers T(n,k) = C(n,k,k-3), n >= 4, 4 <= k <= n. 0
1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 4, 4, 5, 1, 3, 5, 7, 6, 6, 1, 3, 6, 10, 10, 8, 7, 1, 3, 7, 11, 17, 16, 10, 8, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

4,2

COMMENTS

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.

REFERENCES

CRC Handbook of Combinatorial Designs, 1996, p. 263.

W. H. Mills and R. C. Mullin, Coverings and packings, pp. 371-399 of J. H. Dinitz and D. R. Stinson, editors,a Contemporary Design Theory, Wiley, 1992.

LINKS

Table of n, a(n) for n=4..39.

D. Gordon, La Jolla Repository of Coverings

Index entries for covering numbers

EXAMPLE

1; 2 1; 2 3 1; 2 3 4 1; 2 4 4 5 1; ...

CROSSREFS

Sequence in context: A195097 A181845 A183534 * A066019 A051237 A064379

Adjacent sequences:  A066037 A066038 A066039 * A066041 A066042 A066043

KEYWORD

nonn,tabl,more

AUTHOR

N. J. A. Sloane, Dec 30 2001

STATUS

approved

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Last modified June 19 10:42 EDT 2013. Contains 226404 sequences.