The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  X  1  1  X  X  1  1
 0  X 2X  0 X+3 2X  6 X+3 2X+6  6 X+6 2X+6  6 X+3 X+6 2X 2X  6  0  X
 0  0  6  6  3  3  3  6  0  6  0  6  0  6  6  0  6  3  3  3

generates a code of length 20 over Z9[X]/(X^2+3,3X) who´s minimum homogenous weight is 37.

Homogenous weight enumerator: w(x)=1x^0+36x^37+168x^38+12x^39+204x^40+252x^41+10x^42+24x^43+2x^45+6x^46+12x^47+2x^51

The gray image is a code over GF(3) with n=180, k=6 and d=111.
This code was found by Heurico 1.16 in 0.0118 seconds.