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

generates a code of length 31 over Z7[X]/(X^2) who´s minimum homogenous weight is 154.

Homogenous weight enumerator: w(x)=1x^0+246x^154+978x^161+1560x^168+2166x^175+14406x^180+2628x^182+86436x^187+3342x^189+3054x^196+2046x^203+684x^210+102x^217

The gray image is a linear code over GF(7) with n=217, k=6 and d=154.
This code was found by Heurico 1.16 in 5.92 seconds.