The generator matrix

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

generates a code of length 8 over Z49 who´s minimum homogenous weight is 28.

Homogenous weight enumerator: w(x)=1x^0+420x^28+1008x^35+4032x^42+100842x^48+6432x^49+4914x^56

The gray image is a code over GF(7) with n=56, k=6 and d=28.
This code was found by Heurico 1.16 in 0.377 seconds.