The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  7  1  1  1  1
 0  7  0  0  0  7  7 28  0 21  7 42 14 42  0 28  7 42  7 28 28 35 28 14 14 42 21 42  7  7  0 28  7 28  7 28 14  0 14 14  0  0 28 35 28 35 14 42  7  7 42 35  0  0
 0  0  7  0  0 35 28 35  7 28 35 35  7  7  7 21 42 21 21 35  0 28  0  0  7  7 14  0 28 35 42  0 35 28  0 14 21  7 35 42 42 21 21  7 28 14  7 21 21 42 42  0  7  0
 0  0  0  7  0 35 21 21 35 35  7 42  0 14 42 21  7 21 21  7  7  0  7 14 35 42 42 28 42 14 14 14 28 14 42 35 35 21 28 35  7 42 28  0  0 14 28  0 35 35 14 28 42 14
 0  0  0  0  7 35 42  7 42  7  7  0 14  7  7 42 28  0 28 14 21 35 42 14  7  7 21  0 35  0 35 28 21 21  7 35  7 42 35 35 14 21  0 28 35  0 42 21  0 28  7  7 14 21

generates a code of length 54 over Z49 who´s minimum homogenous weight is 287.

Homogenous weight enumerator: w(x)=1x^0+234x^287+996x^294+1488x^301+1890x^308+1992x^315+14406x^318+2118x^322+86436x^325+2340x^329+2160x^336+1794x^343+1056x^350+498x^357+198x^364+42x^371

The gray image is a code over GF(7) with n=378, k=6 and d=287.
This code was found by Heurico 1.16 in 11.9 seconds.