The generator matrix

 1  0  1  1  1  4  1  1  0  0  1  1  1  1  6  1  1  2  1  1  0  1  4  1  2  1  1  0  2  1  1  2  1  1  1  4  6  4  1  1  1  1  1  4  1  1  1  6  1  4  1  1  1  1  1  1  1  1  4  1  1  1  0  1
 0  1  1  0  1  1  4  3  1  1  0  7  5  4  1  1  4  1  4  3  1  1  1  4  1  4  1  1  1  7  2  1  6  1  3  1  1  1  3  3  6  5  4  1  6  2  1  1  1  2  3  7  4  6  5  5  5  3  1  3  5  0  1  4
 0  0  2  0  0  0  0  4  4  4  0  0  4  6  2  6  6  6  2  6  6  6  2  6  0  0  0  6  4  6  0  0  6  2  4  6  0  6  6  2  4  4  4  2  4  6  6  2  4  0  2  0  2  2  6  4  4  4  2  2  2  2  6  2
 0  0  0  2  0  0  4  0  6  6  6  2  6  6  6  2  0  2  6  4  0  6  4  0  2  4  6  2  6  2  6  4  2  0  2  0  4  4  2  0  0  2  4  6  6  0  4  6  0  6  4  4  4  6  2  4  4  2  2  4  2  6  6  4
 0  0  0  0  2  6  6  0  6  0  2  4  2  2  4  4  6  2  0  6  6  6  0  4  0  2  4  6  6  0  0  2  6  4  6  2  0  0  2  0  4  6  2  4  6  4  2  2  6  4  2  2  4  2  0  6  0  0  2  0  6  6  2  2

generates a code of length 64 over Z8 who´s minimum homogenous weight is 57.

Homogenous weight enumerator: w(x)=1x^0+74x^57+156x^58+274x^59+317x^60+394x^61+410x^62+302x^63+370x^64+388x^65+350x^66+280x^67+263x^68+230x^69+124x^70+52x^71+27x^72+20x^73+10x^74+14x^75+12x^76+8x^77+6x^78+6x^79+6x^81+2x^88

The gray image is a code over GF(2) with n=256, k=12 and d=114.
This code was found by Heurico 1.16 in 0.772 seconds.