The generator matrix

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

generates a code of length 20 over GR(16,4) who´s minimum homogenous weight is 46.

Homogenous weight enumerator: w(x)=1x^0+300x^46+528x^47+309x^48+504x^49+3240x^50+3600x^51+2094x^52+2784x^53+11688x^54+12384x^55+7806x^56+10896x^57+30048x^58+28128x^59+18468x^60+21600x^61+37836x^62+29328x^63+11757x^64+7224x^65+15192x^66+5904x^67+438x^68+54x^72+24x^76+9x^80

The gray image is a code over GF(4) with n=80, k=9 and d=46.
This code was found by Heurico 1.16 in 51.7 seconds.