The generator matrix

 1  0  1  1  1  1  1  0  1  1  1  1  X  1  1  X
 0  1  1  2 2X+1  0  2  1  X  X 2X+1 X+2  1 X+1 X+2  1
 0  0 2X  0  X  X 2X 2X  X  0 2X 2X  0  X  0 2X

generates a code of length 16 over Z3[X]/(X^2) who´s minimum homogenous weight is 30.

Homogenous weight enumerator: w(x)=1x^0+112x^30+96x^33+32x^36+2x^48

The gray image is a linear code over GF(3) with n=48, k=5 and d=30.
As d=30 is an upper bound for linear (48,5,3)-codes, this code is optimal over Z3[X]/(X^2) for dimension 5.
This code was found by Heurico 1.16 in 0.000839 seconds.