The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1
 0  X  0  X 2X 2X  0  X 2X 4X 4X 2X 4X  0  X 4X  0  X
 0  0  X 3X 2X 3X 2X  X  X 3X  0 4X 4X 4X 2X  X 3X 3X

generates a code of length 18 over Z5[X]/(X^2) who´s minimum homogenous weight is 65.

Homogenous weight enumerator: w(x)=1x^0+20x^65+52x^70+500x^72+40x^75+4x^85+8x^90

The gray image is a linear code over GF(5) with n=90, k=4 and d=65.
This code was found by Heurico 1.16 in 0.000974 seconds.