5,2

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.

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

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.

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.

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. 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.

Cf.A066009.A column ofA066010.

Sequence in context:A309731A253951A102172*A087940A092387A340360

Adjacent sequences:A011980A011981A011982*A011984A011985A011986

nonn,hard

Next term is <= 157.

approved