%I #13 Feb 02 2020 20:51:03

%S 1,8,20,63,126

%N Covering numbers C(n,8,7).

%C 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.

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

%D 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.

%H D. Applegate, E. M. Rains and N. J. A. Sloane, <a href="http://arXiv.org/abs/math.CO/0205303">On asymmetric coverings and covering numbers</a>, J. Comb. Des. 11 (2003), 218-228.

%H D. Gordon, <a href="http://www.dmgordon.org/cover">La Jolla Repository of Coverings</a>

%H K. J. Nurmela and Patric R. J. Östergård, <a href="http://www.tcs.hut.fi/old/papers/tp1.ps.Z">New coverings of t-sets with (t+1)-sets</a>, J. Combinat. Designs, 7 (1999), 217-226.

%H K. J. Nurmela and Patric R. J. Östergård, <a href="http://www.tcs.hut.fi/old/papers/table3.html">New coverings of t-sets with (t+1)-sets (appendix)</a>, J. Combinat. Designs, 7 (1999), 217-226.

%H <a href="/index/Cor#covnum">Index entries for covering numbers</a>

%Y A column of A066010.

%K nonn,hard

%O 8,2

%A _N. J. A. Sloane_