The generator matrix

 1  0  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  0  1  1  1  1  1  0  1  1  1  1  1  1  1  1  1  3  1  1  1  1  1  1  1  3  1  1  1  1  1  1  1  1  1 6a+6  1  1  1  3  1  1  1  1  1 6a 6a+6  1 3a+6  1  1  1  1  1  1  1  1  1  1 3a  1  1  1  1  1  1  1
 0  1  1  a 7a+7 8a+4 3a+5 8a+5 8a a+5  0 a+5 8a  a 8a+5 3a+7 7a+7 8a+4  1 3a+5  0 3a+7 8a+5 8a+4  1  a 3a+5 7a+7 8a a+5  3 2a+5 a+8 6a+5  1 3a+7 a+3 8a+7 6a+7 8a+3 a+7 8a+3  1 2a+4 4a+8 2a+3 2a+5 2a+5 a+1 3a+4 6a+8 8a+3  1 4a  3 4a+8  1 a+7 2a+8 4a+3 4a+8 5a+2  1  1 a+6  1 8a+2 6a 8a+5 a+3 4a a+3 3a a+1 6a+7 2a+2  1  7 2a+8 4a 2a 7a+7 a+1 8a+4
 0  0 3a+6  0 3a+6  3 6a+6 6a+6  6 3a 3a+6 3a  3  0 6a 6a+3 6a+6  6 6a 3a 6a  6 3a 6a+3 6a 3a+3 3a+6  0  6  3 6a 6a 6a+3  0 6a+3 3a+3 3a  6 3a+3  0 6a+3 6a 3a  3  3 6a 6a+6  3  3 3a+6 3a 3a 6a+3 3a 3a+6  6 3a 3a+3  6  0 3a  0 6a 3a 6a 3a+3 3a+3 3a+3 3a+6 3a+6 6a+3  6 6a+3 3a+6 6a+3 6a  0  6 3a+3 6a+3  0 3a+6 6a+6 3a
 0  0  0  3 3a+6 3a+6  3 3a  3 3a+3 6a 6a+6 6a 3a 3a+3 3a+6  0 6a+3 3a 6a+3 6a+6  6 3a 6a  3  0  3 3a+6 6a+6 3a 3a  6 3a 6a+6  0 3a+3  3 6a+6 3a+6  3  0 6a+3 3a+6  0 6a 6a 3a+3  3 6a+6  6 6a+6 3a+6 3a+6 3a+3 3a 3a+3 6a+6 6a+6  3 6a  0  6  0  3  0  3  6 6a+3 6a+3  3  0 6a 6a  6 3a 6a+6 3a+3 6a 3a+6 3a+6  6  0  3 6a+6

generates a code of length 84 over GR(81,9) who´s minimum homogenous weight is 639.

Homogenous weight enumerator: w(x)=1x^0+592x^639+216x^642+72x^643+288x^644+432x^645+2664x^647+3048x^648+720x^650+1152x^651+4464x^652+6408x^653+3888x^654+11736x^656+7128x^657+4320x^659+4968x^660+13392x^661+15336x^662+9072x^663+20088x^665+13168x^666+18360x^668+20736x^669+41184x^670+42264x^671+20952x^672+42264x^674+20112x^675+29088x^677+25416x^678+45864x^679+40680x^680+18144x^681+28224x^683+13432x^684+376x^693+360x^702+384x^711+264x^720+120x^729+32x^738+24x^747+8x^756

The gray image is a code over GF(9) with n=756, k=6 and d=639.
This code was found by Heurico 1.16 in 50.5 seconds.