The generator matrix

 1  0  1  1  1  1  1  1  1  1  1  1  1  1  1  1  0  1  1  1  1  1  1  1  1  1  2  1  1  1  1  1  1  1  1  1  1  1  1  2  1  1 2a  1  1  1  1  1  1  1  1  1 2a  1  1  1  1  1  1  1  1 2a+2  1  1  1  1  1  1  1  1  1 2a+2  1  1  2  1  1  1  1  0  1  1  1  1 2a^2+2  1  1
 0  1  1  a 3a^2+2 2a^2+3a+1 a^2+3a a^2+3a+3 3a^2+2a+3  0 2a^2+3  a  2 a+2 2a^2+3a+1 2a^2+3a+3  1 3a^2+2 a^2+3a 3a^2+2a+2 a^2+3a+3 3a^2+2a+3 a^2+a 2a^2+3 a^2+3a+1 3a^2+3  1  2 2a 2a^2+2a+3 a+2 2a^2+3a+3 3a^2+3 2a^2+2a+3 2a+1 a^2+a 3a^2+2a+2 2a^2+a+3 a^2+3a+1  1 3a+3 3a^2+2a  1 3a+2 a^2+a+2 a^2+a+1 a^2+1 a^2+a+2 3a 3a^2+2a a^2+a+3 a^2+1  1  1 2a 3a 3a^2 2a^2+a+3 a^2+3a+2 a^2+a+3 a^2+2a+1  1 2a^2+2a 2a^2+2a 2a+1 3a+2 3a^2 3a+3 a^2+3a+2 a^2+a+1 a^2+2a+1  1  2  0 2a^2+2a 3a^2+2 2a^2+3a+1 3a^2+a 3a^2+3  1 3a^2+2a+2 a^2+2a+3 2a^2+3a+3 3a^2+a+2  1 2a+2 3a^2+2a
 0  0 2a^2+2 2a  2  0 2a+2 2a^2+2a+2 2a^2+2a 2a^2 2a 2a^2+2a 2a^2+2 2a^2  2 2a+2 2a^2+2a+2 2a^2+2a+2  0 2a^2+2a  2 2a^2+2a+2 2a 2a^2 2a^2+2 2a+2 2a+2 2a^2+2a+2 2a+2  2  0 2a^2 2a 2a^2+2a+2 2a^2+2a  2  0 2a^2+2a 2a+2 2a^2 2a^2+2 2a 2a 2a^2+2 2a^2+2a 2a^2  0 2a^2+2 2a^2+2a+2 2a^2  0  2 2a^2+2 2a+2 2a 2a+2 2a^2+2 2a 2a^2+2a+2 2a^2+2a 2a^2  2  2 2a^2+2a+2  0  2 2a+2 2a^2+2a+2 2a^2 2a 2a^2+2 2a^2+2a 2a^2+2a  2 2a^2+2a+2  0 2a^2 2a+2  0 2a 2a+2 2a^2  0 2a^2+2a+2 2a+2 2a+2 2a^2+2a+2

generates a code of length 87 over GR(64,4) who´s minimum homogenous weight is 596.

Homogenous weight enumerator: w(x)=1x^0+2240x^596+1624x^597+147x^600+6048x^602+5152x^604+2184x^605+196x^608+2688x^612+1512x^613+49x^616+4704x^618+4256x^620+1848x^621+119x^624

The gray image is a code over GF(8) with n=696, k=5 and d=596.
This code was found by Heurico 1.16 in 0.41 seconds.