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

generates a code of length 50 over GR(64,4) who´s minimum homogenous weight is 304.

Homogenous weight enumerator: w(x)=1x^0+140x^304+945x^312+2296x^320+2870x^328+3682x^336+28672x^343+4354x^344+200704x^351+5103x^352+5320x^360+4263x^368+2373x^376+1148x^384+266x^392+7x^400

The gray image is a code over GF(8) with n=400, k=6 and d=304.
This code was found by Heurico 1.16 in 30.5 seconds.