The generator matrix

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

generates a code of length 75 over GR(64,4) who´s minimum homogenous weight is 496.

Homogenous weight enumerator: w(x)=1x^0+266x^496+749x^504+721x^512+3584x^518+679x^520+25088x^526+371x^528+343x^536+252x^544+238x^552+182x^560+154x^568+98x^576+21x^584+21x^592

The gray image is a code over GF(8) with n=600, k=5 and d=496.
This code was found by Heurico 1.16 in 0.832 seconds.