A066137 Covering numbers C(n,9,8).

1, 9, 25, 84, 185

Offset

9,2

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=9..13.

D. Applegate, E. M. Rains and N. J. A. Sloane, On asymmetric coverings and covering numbers, J. Comb. Des. 11 (2003), 218-228.

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: A322939 A141583 A147413 * A269662 A147428 A147436

Adjacent sequences: A066134 A066135 A066136 * A066138 A066139 A066140

Keyword

nonn,hard

Author

N. J. A. Sloane

Status

approved