The generator matrix

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

generates a code of length 51 over GR(16,4) who´s minimum homogenous weight is 139.

Homogenous weight enumerator: w(x)=1x^0+840x^139+366x^140+792x^141+348x^142+3060x^143+1425x^144+1752x^145+636x^146+5820x^147+2025x^148+2736x^149+888x^150+7200x^151+2625x^152+3108x^153+1128x^154+8400x^155+2601x^156+2904x^157+1212x^158+6564x^159+1893x^160+1920x^161+348x^162+3180x^163+810x^164+576x^165+48x^166+264x^167+21x^168+36x^169+3x^172+3x^176+3x^180

The gray image is a code over GF(4) with n=204, k=8 and d=139.
This code was found by Heurico 1.16 in 16.5 seconds.