The generator matrix

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

generates a code of length 74 over F4[X]/(X^2) who´s minimum homogenous weight is 216.

Homogenous weight enumerator: w(x)=1x^0+312x^216+2304x^218+192x^220+252x^224+192x^228+72x^232+768x^234+3x^256

The gray image is a linear code over GF(4) with n=296, k=6 and d=216.
This code was found by Heurico 1.16 in 50 seconds.