The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  2  4  2  0
 0  2  0  2  0  0  6  6  4  6  4  2  2  0  4  2  2  2  6  2
 0  0  2  2  0  6  2  4  4  4  2  4  2  4  2  6  2  6  0  4
 0  0  0  4  4  4  0  4  0  0  0  4  0  0  4  0  4  4  0  4

generates a code of length 20 over Z8 who´s minimum homogenous weight is 18.

Homogenous weight enumerator: w(x)=1x^0+90x^18+92x^20+60x^22+2x^24+10x^26+1x^32

The gray image is a code over GF(2) with n=80, k=8 and d=36.
This code was found by Heurico 1.16 in 0.275 seconds.