The generator matrix

 1  1  1  1  1
 0  X  0  X 3X
 0  0  X 5X 3X

generates a code of length 5 over Z7[X]/(X^2) who´s minimum homogenous weight is 21.

Homogenous weight enumerator: w(x)=1x^0+60x^21+120x^28+2058x^30+162x^35

The gray image is a linear code over GF(7) with n=35, k=4 and d=21.
This code was found by Heurico 1.16 in 0.000224 seconds.