The generator matrix

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

generates a code of length 21 over Z7[X]/(X^2) who´s minimum homogenous weight is 98.

Homogenous weight enumerator: w(x)=1x^0+258x^98+1170x^105+1656x^112+2688x^119+104940x^126+3870x^133+2508x^140+558x^147

The gray image is a linear code over GF(7) with n=147, k=6 and d=98.
This code was found by Heurico 1.16 in 3.46 seconds.