The generator matrix

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

generates a code of length 94 over GR(64,4) who´s minimum homogenous weight is 646.

Homogenous weight enumerator: w(x)=1x^0+2240x^646+2856x^647+119x^648+6048x^651+3864x^654+3864x^655+224x^656+1680x^662+1176x^663+84x^664+4704x^667+2968x^670+2856x^671+7x^672+77x^680

The gray image is a code over GF(8) with n=752, k=5 and d=646.
This code was found by Heurico 1.16 in 0.472 seconds.