The generator matrix

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

generates a code of length 21 over GR(16,4) who´s minimum homogenous weight is 51.

Homogenous weight enumerator: w(x)=1x^0+408x^51+480x^52+156x^53+144x^54+2340x^55+1725x^56+336x^57+1296x^58+6720x^59+5040x^60+936x^61+3888x^62+12792x^63+7449x^64+1104x^65+3888x^66+10440x^67+4551x^68+540x^69+1092x^71+129x^72+54x^76+24x^80+3x^84

The gray image is a code over GF(4) with n=84, k=8 and d=51.
This code was found by Heurico 1.16 in 4.84 seconds.