The generator matrix

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

generates a code of length 42 over F8[X]/(X^2) who´s minimum homogenous weight is 256.

Homogenous weight enumerator: w(x)=1x^0+721x^256+1988x^264+2947x^272+3710x^280+28672x^287+4592x^288+200704x^295+5635x^296+5761x^304+4508x^312+2212x^320+623x^328+70x^336

The gray image is a linear code over GF(8) with n=336, k=6 and d=256.
This code was found by Heurico 1.16 in 24.4 seconds.