The generator matrix

 1  1  1  1  1  1  1
 0  7  0  0  0  7  7
 0  0  7  0  0 35 28
 0  0  0  7  0 35 21
 0  0  0  0  7 35 42

generates a code of length 7 over Z49 who´s minimum homogenous weight is 21.

Homogenous weight enumerator: w(x)=1x^0+210x^21+840x^28+3402x^35+107478x^42+5718x^49

The gray image is a code over GF(7) with n=49, k=6 and d=21.
This code was found by Heurico 1.16 in 0.283 seconds.