The generator matrix

 1  1  1  1  1  1  1  1  X  X  X  1  1  X X^2 X^2 X^2  X  X X^2  X
 0  2  0  2  0  0  2  2  0  2  2  0  0  0  2  2  0  2  2  0  0
 0  0  2  2  0  2  2  0  2  2  0  0  2  0  2  0  2  2  0  0  0

generates a code of length 21 over Z4[X]/(X^3+2,2X) who´s minimum homogenous weight is 20.

Homogenous weight enumerator: w(x)=1x^0+8x^20+44x^21+4x^22+3x^24+4x^25

The gray image is a code over GF(2) with n=168, k=6 and d=80.
This code was found by Heurico 1.16 in -3.24e-008 seconds.