The generator matrix

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

generates a code of length 24 over F8[X]/(X^2) who´s minimum homogenous weight is 136.

Homogenous weight enumerator: w(x)=1x^0+679x^136+2142x^144+448x^147+3227x^152+9408x^155+5320x^160+65856x^163+7357x^168+153664x^171+8386x^176+4417x^184+1239x^192

The gray image is a linear code over GF(8) with n=192, k=6 and d=136.
This code was found by Heurico 1.16 in 11.8 seconds.