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A011983 Covering numbers C(n,5,4). 3
1, 5, 9, 20, 30, 51, 66, 113 (list; graph; refs; listen; history; text; internal format)
OFFSET
5,2
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.
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.
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.
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.
CROSSREFS
Cf. A066009. A column of A066010.
Sequence in context: A309731 A253951 A102172 * A087940 A092387 A340360
KEYWORD
nonn,hard
AUTHOR
EXTENSIONS
Next term is <= 157.
STATUS
approved

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Last modified March 28 07:46 EDT 2024. Contains 371235 sequences. (Running on oeis4.)