A128037 Maximal possible number of vectors in {0,1,2,3}^n such that the Hamming distance between every two is odd.

4, 4, 6, 9, 12, 12, 14

Offset

1,1

Links

Table of n, a(n) for n=1..7.

N. Alon and E. Lubetzky, Codes and XOR graph products, Combinatorica, 27 (No. 1, 2007), 13-33. [See g_4(n).]

Example

From Bert Dobbelaere, Jan 07 2019: (Start)
Lexicographically earliest maximal sets:
a(1) = 4 {0, 1, 2, 3}
a(2) = 4 {00, 01, 02, 03}
a(3) = 6 {000, 001, 002, 113, 123, 133}
a(4) = 9 {0000, 0001, 0002, 0113, 0123, 0133, 1203, 2203, 3203}
a(5) = 12 {00000, 00001, 00002, 00113, 00123, 00133, 01203, 02203, 03203, 10303, 20303, 30303}
a(6) = 12 {000000, 000001, 000002, 000113, 000123, 000133, 001203, 002203, 003203, 010303, 020303, 030303}
a(7) = 14 {0000000, 0000001, 0000002, 0000113, 0000123, 0000133, 0001203, 0002203, 0003203, 0010303, 0020303, 1130303, 1230303, 1330303}
(End)

Crossrefs

Cf. A128036.

Sequence in context: A163925 A200609 A343985 * A102414 A127799 A213375

Adjacent sequences: A128034 A128035 A128036 * A128038 A128039 A128040

Keyword

nonn,nice,more

Author

Alon Noga (nogaa(AT)post.tau.ac.il) and Eyal Lubetzky (lubetzky(AT)post.tau.ac.il), May 03 2007

Extensions

a(6)-a(7) from Bert Dobbelaere, Jan 07 2019

Status

approved