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

generates a code of length 61 over GR(64,4) who´s minimum homogenous weight is 400.

Homogenous weight enumerator: w(x)=1x^0+308x^400+756x^408+749x^416+595x^424+28672x^427+518x^432+315x^440+329x^448+175x^456+238x^464+49x^472+49x^480+14x^488

The gray image is a code over GF(8) with n=488, k=5 and d=400.
This code was found by Heurico 1.16 in 0.646 seconds.