A011977 Covering numbers C(n,5,2).

1, 3, 3, 4, 5, 6, 7, 9, 10, 12, 13, 15, 16, 18, 19, 21, 21, 27, 28, 30, 30, 37, 38, 40

Offset: 5

Author

N. J. A. Sloane

Keywords

• nonn
• hard

Comments

It is known that 42 <= a(29) <= 43. The next few values are known: a(30) = 48, a(31) = 50, a(32) = 52. - Nathaniel Johnston, Jan 10 2024

References

• CRC Handbook of Combinatorial Designs, 1996, p. 262.

Links

• D. Gordon, La Jolla Repository of Coverings
• Uenal Mutlu (uenalm(AT)metronet.de), Tables of coverings
• Index entries for covering numbers

Crossrefs

Cf. A011975, A240116.

Extensions

a(28) from Nathaniel Johnston, Jan 10 2024