login
A011981
Covering numbers C(n,6,3) (next term is <= 21).
0
1, 4, 4, 7, 10, 11, 15
OFFSET
6,2
REFERENCES
CRC Handbook of Combinatorial Designs, 1996, p. 262.
CROSSREFS
Sequence in context: A371556 A214990 A185670 * A238131 A212532 A109544
KEYWORD
nonn,hard
AUTHOR
STATUS
approved