Best binary codes

Binary (21,18)-code with minimal distance 2


[100000000000000000100]
[010000000000000000100]
[001000000000000000100]
[000100000000000000100]
[000010000000000000100]
[000001000000000000100]
[000000100000000000100]
[000000010000000000100]
[000000001000000000100]
[000000000100000000100]
[000000000010000000100]
[000000000001000000100]
[000000000000100000100]
[000000000000010000100]
[000000000000001000100]
[000000000000000100100]
[000000000000000010100]
[000000000000000001100]