The generator matrix

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

generates a code of length 5 over Z7[X]/(X^2) who´s minimum homogenous weight is 18.

Homogenous weight enumerator: w(x)=1x^0+420x^18+60x^21+5880x^24+5040x^25+120x^28+55566x^30+35280x^31+15120x^32+162x^35

The gray image is a linear code over GF(7) with n=35, k=6 and d=18.
This code was found by Heurico 1.16 in 0.0721 seconds.