The generator matrix

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

generates a code of length 60 over F4[X,sigma]/(X^2) who´s minimum homogenous weight is 161.

Homogenous weight enumerator: w(x)=1x^0+564x^161+984x^162+840x^163+681x^164+2604x^165+2904x^166+2736x^167+1764x^168+5880x^169+6624x^170+5412x^171+3543x^172+11520x^173+10764x^174+8400x^175+6504x^176+17748x^177+16224x^178+11868x^179+8460x^180+22152x^181+18936x^182+12444x^183+7872x^184+18336x^185+14784x^186+9324x^187+4674x^188+10032x^189+6684x^190+3576x^191+1068x^192+3072x^193+1800x^194+684x^195+153x^196+252x^197+168x^198+12x^199+21x^200+39x^204+15x^208+18x^212+3x^216

The gray image is a linear code over GF(4) with n=240, k=9 and d=161.
This code was found by Heurico 1.16 in 867 seconds.