The generator matrix

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

generates a code of length 38 over GR(64,4) who´s minimum homogenous weight is 248.

Homogenous weight enumerator: w(x)=1x^0+2002x^248+896x^249+280x^252+952x^253+672x^254+10696x^255+16142x^256+4592x^257+3584x^259+3920x^260+6160x^261+2240x^262+23408x^263+32228x^264+6944x^265+25088x^267+13720x^268+14392x^269+4256x^270+37576x^271+43190x^272+9072x^273+42x^280+35x^288+56x^296

The gray image is a code over GF(8) with n=304, k=6 and d=248.
This code was found by Heurico 1.16 in 7.34 seconds.