The generator matrix

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

generates a code of length 69 over F4[X,sigma]/(X^2) who´s minimum homogenous weight is 196.

Homogenous weight enumerator: w(x)=1x^0+1443x^196+3009x^200+3507x^204+3084x^208+2442x^212+1656x^216+957x^220+273x^224+3x^232+6x^240+3x^244

The gray image is a linear code over GF(4) with n=276, k=7 and d=196.
This code was found by Heurico 1.16 in 5.94 seconds.