Binary (21,13)-code with minimal distance 4

[100000001010000000100]
[010000001001000000100]
[001000001000100000100]
[000100001000010000100]
[000010001000001000100]
[000001001000000100100]
[000000101000000010100]
[000000011000000001100]
[000000000010001100010]
[000000000001001010010]
[000000000000101001010]
[000000000000011000110]
[000000000000000111111]