The generator matrix

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

generates a code of length 21 over GR(16,4) who´s minimum homogenous weight is 48.

Homogenous weight enumerator: w(x)=1x^0+258x^48+252x^49+192x^50+492x^51+1533x^52+2556x^53+1812x^54+3024x^55+7662x^56+10200x^57+5616x^58+11304x^59+19464x^60+26424x^61+12984x^62+28656x^63+29352x^64+34092x^65+13488x^66+17100x^67+18243x^68+12492x^69+2772x^70+864x^71+1224x^72+66x^76+15x^80+6x^84

The gray image is a code over GF(4) with n=84, k=9 and d=48.
This code was found by Heurico 1.16 in 56.2 seconds.