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

generates a code of length 51 over Z49 who´s minimum homogenous weight is 287.

Homogenous weight enumerator: w(x)=1x^0+420x^287+42x^288+504x^294+756x^295+456x^301+4536x^302+228x^308+9072x^309+222x^315+174x^322+174x^329+138x^336+72x^343+6x^350+6x^357

The gray image is a code over GF(7) with n=357, k=5 and d=287.
This code was found by Heurico 1.16 in 7.99 seconds.