The generator matrix

 1  0  1  1  1  1  1  1  1  1  1  1  1
 0  1  1  3 5X+2  6 5X+4  5  0 5X+1  3 5X+2  6
 0  0 5X  0 5X  X 5X  X 6X 2X 3X 6X 3X
 0  0  0  X 4X 4X 3X 6X  0 6X 6X 3X 4X

generates a code of length 13 over Z7[X]/(X^2) who´s minimum homogenous weight is 63.

Homogenous weight enumerator: w(x)=1x^0+324x^63+1470x^66+420x^70+6174x^72+17640x^73+540x^77+37044x^79+52920x^80+810x^84+306x^91

The gray image is a linear code over GF(7) with n=91, k=6 and d=63.
This code was found by Heurico 1.16 in 0.612 seconds.