The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  X  X
 0  X  0  0  X  X 4X 2X 3X  0  X 3X 3X 6X 4X  X 2X 2X  X  X
 0  0  X  0 5X 4X 3X 5X 6X 3X 3X 3X 5X 6X  0 5X 4X 4X 3X 5X
 0  0  0  X 5X  X 2X 6X 6X 4X  X  0 2X 3X 3X 6X  0  X 2X 3X

generates a code of length 20 over Z7[X]/(X^2) who´s minimum homogenous weight is 105.

Homogenous weight enumerator: w(x)=1x^0+432x^105+294x^108+528x^112+3528x^115+408x^119+10584x^122+408x^126+528x^133+96x^140

The gray image is a linear code over GF(7) with n=140, k=5 and d=105.
This code was found by Heurico 1.16 in 0.198 seconds.