The generator matrix

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

generates a code of length 6 over F8[X]/(X^2) who´s minimum homogenous weight is 24.

Homogenous weight enumerator: w(x)=1x^0+140x^24+448x^28+525x^32+14336x^35+6272x^36+1596x^40+114688x^42+100352x^43+21952x^44+1834x^48

The gray image is a linear code over GF(8) with n=48, k=6 and d=24.
This code was found by Heurico 1.16 in 0.309 seconds.