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

generates a code of length 84 over Z5[X]/(X^2) who´s minimum homogenous weight is 331.

Homogenous weight enumerator: w(x)=1x^0+220x^331+64x^335+160x^336+48x^340+20x^341+8x^345+100x^346+4x^370

The gray image is a linear code over GF(5) with n=420, k=4 and d=331.
This code was found by Heurico 1.16 in 0.102 seconds.