A011984 Covering numbers C(n,6,4).

1, 5, 7, 12, 20, 32

Offset

6,2

Comments

a(12) <= 41.

References

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

Links

Table of n, a(n) for n=6..11.

D. Gordon, La Jolla Repository of Coverings.

Wikipedia, Covering design.

Index entries for covering numbers.

Crossrefs

Sequence in context: A373669 A247027 A020686 * A280291 A195557 A063187

Adjacent sequences: A011981 A011982 A011983 * A011985 A011986 A011987

Keyword

nonn,more,hard

Author

N. J. A. Sloane

Extensions

Missing a(6) inserted by Pontus von Brömssen, Feb 10 2026

Status

approved