The generator matrix

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

generates a code of length 17 over GR(64,4) who´s minimum homogenous weight is 88.

Homogenous weight enumerator: w(x)=1x^0+378x^88+1708x^96+3066x^104+5936x^112+229376x^119+10542x^120+7651x^128+3486x^136

The gray image is a code over GF(8) with n=136, k=6 and d=88.
This code was found by Heurico 1.16 in 6.85 seconds.