This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A011983 #19 Aug 24 2023 13:42:22 %S A011983 1,5,9,20,30,51,66,113 %N A011983 Covering numbers C(n,5,4). %C A011983 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 A011983 CRC Handbook of Combinatorial Designs, 1996, p. 263. %D A011983 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 A011983 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 A011983 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 A011983 D. Gordon, <a href="http://www.dmgordon.org/cover">La Jolla Repository of Coverings</a> %H A011983 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 A011983 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 A011983 <a href="/index/Cor#covnum">Index entries for covering numbers</a> %Y A011983 Cf. A066009. A column of A066010. %K A011983 nonn,hard %O A011983 5,2 %A A011983 _N. J. A. Sloane_ %E A011983 Next term is <= 157.