The generator matrix

 1  0  0  1  1  1  1  1  1  1  1  1  1  1 2a^2+2
 0  1  0  1  a a^2 3a+3 a^2+3a a^2+3a+3 a^2+2a+1 2a^2+2 2a^2+3 a+2 a^2+2  1
 0  0  1 a^2+2a+1  a 3a^2+3a+2  1 a^2+3a+3 2a^2+3a+1 a^2  3 a^2+a+3 2a^2+2 3a^2+2 a^2+2a+3

generates a code of length 15 over GR(64,4) who´s minimum homogenous weight is 91.

Homogenous weight enumerator: w(x)=1x^0+1344x^91+4536x^92+189x^96+2688x^98+18816x^99+27216x^100+168x^104+57344x^105+18816x^106+65856x^107+65016x^108+42x^112+112x^120

The gray image is a code over GF(8) with n=120, k=6 and d=91.
This code was found by Heurico 1.16 in 1.83 seconds.