The generator matrix

 1  1  1  1  1  1
 0  7  0  0  7  7
 0  0  7  0 35 28
 0  0  0  7 35  7

generates a code of length 6 over Z49 who´s minimum homogenous weight is 21.

Homogenous weight enumerator: w(x)=1x^0+120x^21+360x^28+972x^35+14406x^36+948x^42

The gray image is a code over GF(7) with n=42, k=5 and d=21.
This code was found by Heurico 1.16 in 0.00593 seconds.