The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1
 0  X  0  0  0  X  X  X a*X  0  X a*X a*X a*X a*X  0 a^4*X  X
 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^4*X a^4*X
 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^4*X
 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*X a*X

generates a code of length 18 over F8[X]/(X^2) who´s minimum homogenous weight is 96.

Homogenous weight enumerator: w(x)=1x^0+532x^96+2184x^104+3136x^112+6384x^120+229376x^126+10395x^128+7112x^136+3024x^144

The gray image is a linear code over GF(8) with n=144, k=6 and d=96.
This code was found by Heurico 1.16 in 7.65 seconds.