The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  X  1  1  X
 0  X  0 X^2 2X 2X^2+X  X 2X^2+2X 2X X^2 2X^2+X 2X^2+2X  0 X^2 2X^2+2X 2X^2 2X  0 2X^2+X 2X^2+X
 0  0  X 2X^2+2X X^2 2X^2+2X  X 2X^2+X X^2+2X X^2 2X^2+X 2X X^2 2X^2+X  X  0 2X^2 2X X^2+2X 2X^2

generates a code of length 20 over Z3[X]/(X^3) who´s minimum homogenous weight is 36.

Homogenous weight enumerator: w(x)=1x^0+168x^36+324x^38+294x^39+486x^40+648x^41+144x^42+90x^45+30x^48+2x^54

The gray image is a linear code over GF(3) with n=180, k=7 and d=108.
This code was found by Heurico 1.16 in 0.00797 seconds.