The generator matrix

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

generates a code of length 18 over F8[X]/(X^2) who´s minimum homogenous weight is 104.

Homogenous weight enumerator: w(x)=1x^0+224x^104+56x^105+504x^107+2065x^112+1176x^113+2968x^115+14336x^119+19516x^120+8232x^121+10472x^123+100352x^127+66829x^128+19208x^129+14728x^131+1148x^136+329x^144

The gray image is a linear code over GF(8) with n=144, k=6 and d=104.
This code was found by Heurico 1.16 in 3.15 seconds.