The generator matrix

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

generates a code of length 18 over F8[X]/(X^2) who´s minimum homogenous weight is 120.

Homogenous weight enumerator: w(x)=1x^0+1008x^120+3087x^128

The gray image is a linear code over GF(8) with n=144, k=4 and d=120.
This code was found by Heurico 1.16 in 0.00144 seconds.