The generator matrix

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

generates a code of length 18 over GR(16,4) who´s minimum homogenous weight is 46.

Homogenous weight enumerator: w(x)=1x^0+192x^46+132x^48+576x^50+360x^52+1344x^54+480x^56+960x^58+27x^64+24x^68

The gray image is a code over GF(4) with n=72, k=6 and d=46.
This code was found by Heurico 1.16 in 2.33 seconds.