The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  X  1  1  1
 0  X  0  0  0  X  X  X a*X  0  X a*X a*X a*X a*X  0  X a^6*X a^4*X  0
 0  0  X  0  0 a^6*X a^5*X a^4*X a^4*X  X a^3*X a^6*X  0  X a^5*X a*X a^3*X  0 a^6*X  0
 0  0  0  X  0  X a^5*X a*X a^3*X a^2*X a^6*X  0 a^5*X  X a*X a^4*X a^3*X a^2*X  X  0
 0  0  0  0  X a^6*X a^3*X a*X a^5*X a*X a^2*X a^2*X a^3*X  0 a*X  X a^2*X a^4*X a^3*X  0

generates a code of length 20 over F8[X]/(X^2) who´s minimum homogenous weight is 104.

Homogenous weight enumerator: w(x)=1x^0+273x^104+1211x^112+2387x^120+3836x^128+28672x^133+6895x^136+200704x^141+9205x^144+6349x^152+2611x^160

The gray image is a linear code over GF(8) with n=160, k=6 and d=104.
This code was found by Heurico 1.16 in 8.46 seconds.