A066041 - OEIS

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A066041

Triangle of covering numbers T(n,k) = C(n,k,k-4), n >= 5, 5 <= k <= n.

1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 5, 1, 2, 4, 6, 5, 6, 1, 3, 6, 8, 9, 7, 7, 1, 3, 6, 11, 12, 12, 9, 8, 1

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

5,2

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 Jeffrey H. Dinitz and D. R. Stinson, editors, Contemporary Design Theory, Wiley, 1992.

LINKS

Table of n, a(n) for n=5..40.

D. Gordon, La Jolla Repository of Coverings

Index entries for covering numbers

EXAMPLE

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

CROSSREFS

Sequence in context: A194905 A243730 A133994 * A194965 A243712 A256553

Adjacent sequences: A066038 A066039 A066040 * A066042 A066043 A066044

KEYWORD

nonn,tabl,more

AUTHOR

N. J. A. Sloane, Dec 30 2001

STATUS

approved