The generator matrix

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

generates a code of length 57 over GR(16,4) who´s minimum homogenous weight is 164.

Homogenous weight enumerator: w(x)=1x^0+924x^164+1254x^168+726x^172+417x^176+648x^180+111x^184+6x^188+6x^192+3x^200

The gray image is a code over GF(4) with n=228, k=6 and d=164.
This code was found by Heurico 1.16 in 0.354 seconds.