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

generates a code of length 76 over GR(16,4) who´s minimum homogenous weight is 220.

Homogenous weight enumerator: w(x)=1x^0+186x^220+600x^221+315x^224+1344x^225+267x^228+240x^229+18x^232+288x^233+96x^236+312x^237+60x^240+288x^241+69x^244+6x^248+3x^252+3x^268

The gray image is a code over GF(4) with n=304, k=6 and d=220.
This code was found by Heurico 1.16 in 0.404 seconds.