The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  2
 0  2  0  0  0  2  2  2 2a  0  2 2a 2a 2a 2a  0 2a^2+2a 2a^2  2
 0  0  2  0  0 2a^2+2 2a^2+2a+2 2a^2+2a 2a^2+2a  2 2a+2 2a^2+2  0  2 2a^2+2a+2 2a 2a+2  2  0
 0  0  0  2  0  2 2a^2+2a+2 2a 2a+2 2a^2 2a^2+2  0 2a^2+2a+2  2 2a 2a^2 2a 2a^2+2a  0
 0  0  0  0  2 2a^2+2 2a+2 2a 2a^2+2a+2 2a 2a^2 2a^2 2a+2  0 2a 2a^2+2a 2a^2+2a 2a^2 2a^2+2a

generates a code of length 19 over GR(64,4) who´s minimum homogenous weight is 104.

Homogenous weight enumerator: w(x)=1x^0+889x^104+2114x^112+3899x^120+28672x^126+6531x^128+200704x^134+9919x^136+6874x^144+2541x^152

The gray image is a code over GF(8) with n=152, k=6 and d=104.
This code was found by Heurico 1.16 in 19.3 seconds.