%I #19 Aug 24 2023 13:42:22
%S 1,5,9,20,30,51,66,113
%N Covering numbers C(n,5,4).
%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 D. De Caen, D. L. Kreher, S. P. Radziszowski, and W. H. Mills, On the covering of t-sets with (t+1)-sets: C(9,5,4) and C(10,6,5). Discrete Math. 92 (1991), no. 1-3, 65-77.
%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="https://arxiv.org/abs/math/0205303">On asymmetric coverings and covering numbers</a>, arXiv:math/0205303 [math.CO], 2002; 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 Cf. A066009. A column of A066010.
%K nonn,hard
%O 5,2
%A _N. J. A. Sloane_
%E Next term is <= 157.