The generator matrix

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

generates a code of length 21 over Z7[X]/(X^2) who´s minimum homogenous weight is 115.

Homogenous weight enumerator: w(x)=1x^0+630x^115+252x^116+156x^119+588x^120+3150x^122+672x^123+96x^126+3528x^127+6510x^129+1134x^130+36x^133+24x^140+30x^147

The gray image is a linear code over GF(7) with n=147, k=5 and d=115.
This code was found by Heurico 1.16 in 0.829 seconds.