A066225 Covering numbers C(n,n-4,n-5).

3, 7, 14, 30, 50, 84, 126, 185, 259, 357, 476

Offset: 6

Author

N. J. A. Sloane

Keywords

• nonn
• hard
• more

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

• D. Applegate, E. M. Rains and N. J. A. Sloane, On asymmetric coverings and covering numbers, arXiv:math/0205303 [math.CO], 2002; J. Comb. Des. 11 (2003), 218-228.
• D. Gordon, La Jolla Repository of Coverings
• K. Markström, Covering designs.
• 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.
• A. Sidorenko, On Turan numbers of the complete 4-graphs, Discr. Math., 344 (2021), #112544.
• Index entries for covering numbers

Crossrefs

A column of A066010.

A036830 is a lower bound.

Extensions

More terms from Sidorenko (2021) added by N. J. A. Sloane, Oct 31 2021