A011976 Covering numbers C(n,4,2).

1, 3, 3, 5, 6, 8, 9, 11, 12, 13, 18, 19, 20, 26, 27, 31, 35, 37, 39, 46, 48, 50, 59, 61, 63, 73, 75, 78, 88, 91, 94, 105, 108, 111, 124, 127, 130, 144, 147, 151, 165, 169, 173, 188, 192, 196, 213, 217, 221, 239, 243, 248, 266, 271, 276, 295, 300, 305, 326

Offset: 4

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Comments

Only differs from A240115 when n = 7, 9, 10, or 19. - Nathaniel Johnston, Jan 10 2024

References

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

Links

• D. Gordon, La Jolla Repository of Coverings
• Index entries for covering numbers

Crossrefs

Cf. A011975, A011977.

Extensions

a(21)-a(62) from Nathaniel Johnston, Jan 10 2024