Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
A004045
Minimal size of binary code of length n such that every vector is within distance 1 of at least 2 codewords.
0
2, 3, 4, 8, 12, 20, 32
OFFSET
1,1
LINKS
H. Hamalainen et al., Football pools - a game for mathematicians, Amer. Math. Monthly, 102 (1995), 579-588.
EXAMPLE
From Paul Tabatabai, Mar 02 2020: (Start)
Lexicographically first optimal code for n = 6:
0 1 2 4 8 23 27 29 30 31 39 43 45 46 47 48 49 50 52 56.
Lexicographically first optimal code for n = 7:
0 1 6 7 24 25 30 31 42 43 44 45 50 51 52 53 74 75 76 77 82 83 84 85 96 97 102 103 120 121 126 127. (End)
CROSSREFS
Sequence in context: A222124 A222125 A222126 * A060200 A057608 A060984
KEYWORD
nonn,hard,more
EXTENSIONS
a(6)-a(7) from Paul Tabatabai, Mar 02 2020
STATUS
approved