The generator matrix

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

generates a code of length 39 over F8[X]/(X^2) who´s minimum homogenous weight is 256.

Homogenous weight enumerator: w(x)=1x^0+2877x^256+448x^259+1344x^260+4480x^261+6832x^262+7168x^263+15015x^264+448x^266+7168x^267+8064x^268+16128x^269+15456x^270+9856x^271+21539x^272+3136x^274+24640x^275+19264x^276+29568x^277+24304x^278+15232x^279+29050x^280+56x^288+63x^296+7x^304

The gray image is a linear code over GF(8) with n=312, k=6 and d=256.
This code was found by Heurico 1.16 in 7.37 seconds.