A066140 Covering numbers C(n,n-3,n-4).

3, 6, 12, 20, 30, 45, 63, 84

Offset

5,1

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..12.

D. Gordon, La Jolla Repository of Coverings

K. J. Nurmela and Patric R. J. Östergård, New coverings of t-sets with (t+1)-sets, J. Combinat. Designs, 7 (1999), 217-226.

K. J. Nurmela and Patric R. J. Östergård, New coverings of t-sets with (t+1)-sets (appendix), J. Combinat. Designs, 7 (1999), 217-226.

Index entries for covering numbers

Crossrefs

A column of A066010.

Sequence in context: A160732 A320608 A246147 * A200067 A061061 A361272

Adjacent sequences: A066137 A066138 A066139 * A066141 A066142 A066143

Keyword

nonn

Author

N. J. A. Sloane

Status

approved