The generator matrix

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

generates a code of length 46 over GR(16,4) who´s minimum homogenous weight is 128.

Homogenous weight enumerator: w(x)=1x^0+1284x^128+3279x^132+3816x^136+3525x^140+3087x^144+1209x^148+177x^152+3x^156+3x^168

The gray image is a code over GF(4) with n=184, k=7 and d=128.
This code was found by Heurico 1.16 in 1.2 seconds.