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

generates a code of length 91 over Z5[X]/(X^2) who´s minimum homogenous weight is 340.

Homogenous weight enumerator: w(x)=1x^0+116x^340+380x^345+496x^350+428x^355+500x^356+340x^360+4000x^361+284x^365+8000x^366+232x^370+220x^375+124x^380+136x^385+92x^390+60x^395+64x^400+68x^405+44x^410+28x^415+4x^420+4x^425+4x^445

The gray image is a linear code over GF(5) with n=455, k=6 and d=340.
This code was found by Heurico 1.16 in 1.69 seconds.