The generator matrix

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

generates a code of length 58 over GR(64,4) who´s minimum homogenous weight is 396.

Homogenous weight enumerator: w(x)=1x^0+5880x^396+3136x^398+238x^400+7056x^404+896x^406+168x^408+12152x^412+3136x^414+91x^416+14x^448

The gray image is a code over GF(8) with n=464, k=5 and d=396.
This code was found by Heurico 1.16 in 19.7 seconds.