The generator matrix

 1  0  1  1  1  1  1  1  1  0  1  1  1  1  1  1  1  1  1  1
 0  1  1  a 7a+7 8a+4 3a+5 8a+5 7a+7  1 8a a+5  0  a a+5 3a+7 3a+7 8a 8a  0
 0  0 3a+6  0 3a+6  3 6a+6 6a+6  3 6a+6  0 3a+3 3a 3a 6a+3  6  6  6 6a+6  3
 0  0  0  3 3a+6 3a+6  3 3a 3a 3a+3 6a 3a+3 3a+3 6a+6 6a+6  3 6a+3 3a+6 3a+3 3a+3

generates a code of length 20 over GR(81,9) who´s minimum homogenous weight is 135.

Homogenous weight enumerator: w(x)=1x^0+328x^135+216x^136+3752x^144+5184x^145+17496x^152+42672x^153+41472x^154+139968x^161+167248x^162+110592x^163+1960x^171+552x^180

The gray image is a code over GF(9) with n=180, k=6 and d=135.
This code was found by Heurico 1.16 in 8.82 seconds.