The generator matrix

 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  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  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  2  0  0  2  0  2  2 2a+2 2a+2 2a+2 2a+2 2a+2 2a+2  0  0  2  2  0  0  2  2 2a+2 2a+2  0  2 2a 2a+2  0  2 2a 2a+2  0  2 2a 2a+2  0  2 2a+2  0  2 2a+2  0  2 2a+2  0  2 2a+2  0  2 2a+2 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a  0  0  0  2  2  0  2  2  0 2a  2 2a+2  0  2 2a 2a+2 2a 2a  0 2a 2a 2a+2 2a  0
 0  0  2  0 2a+2  2 2a+2  0 2a+2 2a+2  2  2 2a+2  2  0  2 2a+2  0  0  2 2a+2  0 2a+2  2 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a 2a+2  2  0 2a+2  2  0 2a+2  2  0 2a 2a  0 2a+2  2 2a  0  0  0  2  2  2  0  2 2a 2a+2 2a+2 2a+2 2a+2  0  0  2 2a+2 2a  2 2a+2 2a 2a  0  0 2a 2a+2  2  2 2a+2 2a 2a 2a+2  0 2a  2  0 2a+2
 0  0  0  2  2  2 2a 2a+2  0  2  0  2 2a 2a 2a 2a+2  0 2a 2a+2 2a 2a+2  2 2a+2 2a+2  0 2a+2  0 2a+2  2  2 2a+2 2a 2a 2a  2  0 2a+2  0  2 2a 2a+2 2a+2  2  2 2a 2a+2  0  0  0 2a  2  0  2 2a 2a+2 2a  2 2a+2  0 2a 2a+2 2a  2  0  0  2 2a+2  0  2 2a  2  0  0  2 2a  2 2a 2a  0 2a  0  2  0 2a 2a  0  2 2a

generates a code of length 88 over GR(16,4) who´s minimum homogenous weight is 256.

Homogenous weight enumerator: w(x)=1x^0+63x^256+63x^260+822x^264+12x^268+27x^272+15x^276+12x^280+6x^284+3x^352

The gray image is a code over GF(4) with n=352, k=5 and d=256.
This code was found by Heurico 1.16 in 0.125 seconds.