The generator matrix

 1  0  1  1  1  1  1  1  1  0  1  1  1  0  1  1  X  1  1  1  1  1  1  1  X  1  1  1  1 aX  1  1  1  1  1  1  1  X  X  1  1 (a+1)X  1 aX  1  1  X  1  1
 0  1  1  a (a+1)X+a+1  0 (a+1)X+1  a (a+1)X+a+1  1  0  a (a+1)X+1  1 (a+1)X+a+1 X+a  1  X (a+1)X+1 aX+a+1 X+a  X  1 aX+a+1  1  X aX+1 a+1 X+a  1  0  X aX aX+1 aX+1  a (a+1)X+a  1  1 aX+a+1 (a+1)X+a  1 (a+1)X+a  1 (a+1)X+1 aX+1  X (a+1)X X+a+1
 0  0 (a+1)X  0  X  X (a+1)X  X (a+1)X  X  0  0  X  X  0 (a+1)X aX aX  0 (a+1)X aX (a+1)X aX aX (a+1)X  X  X  0  X (a+1)X (a+1)X (a+1)X  0 (a+1)X aX  X  0 (a+1)X aX  0  0 aX (a+1)X  0  X  X aX  0 aX
 0  0  0  X aX  X aX (a+1)X (a+1)X  0  X (a+1)X  0 aX aX (a+1)X  0  X  0 aX (a+1)X  X  0 aX  0  0 aX (a+1)X  X aX  0 aX (a+1)X (a+1)X  X aX  0 (a+1)X (a+1)X  X aX  X  0 (a+1)X  X (a+1)X (a+1)X aX (a+1)X

generates a code of length 49 over F4[X,sigma]/(X^2) who´s minimum homogenous weight is 138.

Homogenous weight enumerator: w(x)=1x^0+336x^138+240x^140+756x^142+258x^144+732x^146+192x^148+468x^150+216x^152+612x^154+84x^156+168x^158+9x^160+12x^164+12x^168

The gray image is a linear code over GF(4) with n=196, k=6 and d=138.
This code was found by Heurico 1.16 in 0.176 seconds.