The generator matrix

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

generates a code of length 19 over GR(16,4) who´s minimum homogenous weight is 40.

Homogenous weight enumerator: w(x)=1x^0+60x^40+345x^44+615x^48+2247x^52+5871x^56+6165x^60+708x^64+237x^68+105x^72+30x^76

The gray image is a code over GF(4) with n=76, k=7 and d=40.
This code was found by Heurico 1.16 in 0.503 seconds.