The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  2  1  1  1  1
 0  2  0  6  0  6  4  6  0  6  0  6  0  6  4  2  4  2  2  0  4
 0  0  4  0  0  0  4  0  0  4  4  4  0  4  4  4  0  4  0  4  4
 0  0  0  4  0  0  0  4  4  4  4  4  4  0  4  0  4  4  4  4  4
 0  0  0  0  4  4  4  4  4  0  0  4  0  4  4  4  0  0  4  4  0

generates a code of length 21 over Z8 who´s minimum homogenous weight is 18.

Homogenous weight enumerator: w(x)=1x^0+21x^18+50x^20+128x^21+34x^22+12x^24+9x^26+1x^40

The gray image is a code over GF(2) with n=84, k=8 and d=36.
This code was found by Heurico 1.16 in 0.00802 seconds.