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

generates a code of length 58 over Z49 who´s minimum homogenous weight is 341.

Homogenous weight enumerator: w(x)=1x^0+882x^341+90x^343+294x^348+210x^350+882x^355+42x^357

The gray image is a code over GF(7) with n=406, k=4 and d=341.
This code was found by Heurico 1.16 in 0.0487 seconds.