The generator matrix

 1  1  1  1  1  1  1
 0  2  0  0  0  2  2
 0  0  2  0  0 2a^2+2 2a^2+2a+2
 0  0  0  2  0  2 2a^2+2a+2
 0  0  0  0  2 2a^2+2 2a+2

generates a code of length 7 over GR(64,4) who´s minimum homogenous weight is 24.

Homogenous weight enumerator: w(x)=1x^0+245x^24+1225x^32+5586x^40+12838x^48+229376x^49+12873x^56

The gray image is a code over GF(8) with n=56, k=6 and d=24.
This code was found by Heurico 1.16 in 0.788 seconds.