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

generates a code of length 58 over F8[X]/(X^2) who´s minimum homogenous weight is 400.

Homogenous weight enumerator: w(x)=1x^0+161x^400+3584x^406+336x^408+7x^448+7x^464

The gray image is a linear code over GF(8) with n=464, k=4 and d=400.
This code was found by Heurico 1.16 in 0.0317 seconds.