The generator matrix

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

generates a code of length 77 over GR(64,4) who´s minimum homogenous weight is 526.

Homogenous weight enumerator: w(x)=1x^0+1288x^526+161x^528+1568x^529+6272x^531+4760x^534+175x^536+2240x^537+1792x^539+1400x^542+42x^544+3360x^545+6272x^547+3304x^550+49x^552+56x^560+28x^568

The gray image is a code over GF(8) with n=616, k=5 and d=526.
This code was found by Heurico 1.16 in 27 seconds.