The generator matrix

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

generates a code of length 31 over Z7[X]/(X^2) who´s minimum homogenous weight is 171.

Homogenous weight enumerator: w(x)=1x^0+1134x^171+252x^174+1440x^175+1260x^176+7014x^177+6762x^178+588x^180+3024x^181+7116x^182+3360x^183+10962x^184+11298x^185+3528x^187+9072x^188+14310x^189+5670x^190+17010x^191+13734x^192+66x^196+36x^203+12x^210

The gray image is a linear code over GF(7) with n=217, k=6 and d=171.
This code was found by Heurico 1.16 in 2.08 seconds.