The generator matrix

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

generates a code of length 96 over GR(64,4) who´s minimum homogenous weight is 640.

Homogenous weight enumerator: w(x)=1x^0+154x^640+896x^646+56x^647+840x^648+1456x^650+3696x^651+5096x^654+1568x^655+3038x^656+6664x^658+11144x^659+9184x^662+4368x^663+5376x^664+11592x^666+18312x^667+14448x^670+11424x^671+12047x^672+22680x^674+33432x^675+19040x^678+11256x^679+10241x^680+14952x^682+19432x^683+8680x^686+322x^688+196x^696+161x^704+147x^712+77x^720+70x^728+35x^736+42x^744+21x^752

The gray image is a code over GF(8) with n=768, k=6 and d=640.
This code was found by Heurico 1.16 in 23.9 seconds.