The generator matrix

 1  0  1  1  1  6  1  1  6  1  1  0  1  1  4  1  1  2  1  1  2  1  1  4  1  1  0  1  1  6  1  1  1  1  0  6  1  1  1  1  1  1  1  1  0  4  2  2  4  2  2  4  2  2  2  2  0  2  2  4  1  1  1  1  1  1  1  1  1
 0  1  3  6  5  1  0  3  1  6  5  1  4  7  1  2  1  1  4  7  1  2  1  1  0  3  1  6  5  1  0  6  3  5  1  1  4  2  7  1  4  2  7  1  2  1  0  6  1  4  2  2  1  1  0  6  2  4  2  2  0  0  4  4  3  3  7  7  0
 0  0  4  4  0  4  4  0  0  0  4  4  4  4  4  0  0  0  0  0  4  4  4  0  0  0  4  4  4  0  4  0  4  0  0  4  4  0  4  0  0  4  0  4  4  4  4  4  0  4  4  4  4  0  0  0  0  0  0  0  0  4  4  0  0  4  4  0  0

generates a code of length 69 over Z8 who´s minimum homogenous weight is 68.

Homogenous weight enumerator: w(x)=1x^0+14x^68+90x^69+12x^70+1x^72+4x^73+1x^74+2x^77+2x^78+1x^82

The gray image is a code over GF(2) with n=276, k=7 and d=136.
This code was found by Heurico 1.16 in 0.093 seconds.