[4^(n+1)*3^(2n+2)+2^(2n)*9^(n+2)]/6^2n=117
[4^(n+1)*3^(2n+2)+2^(2n)*9^(n+2)]/6^2n=
= [2^(2n+2)*3^(2n+2)+2^(2n)*9^(n+2)]/6^2n=
=[6^(2n+2)+2^(2n)*9^(n+2)]/6^2n=
=[(6^2)^(n+1)+2^(2n)*9^(n+2)]/6^2n=
= [36^(n+1)+2^(2n)*9^(n+2)]/6^2n=
=36^(n+1)/36^n+2^(2n)*9^(n+2)]/6^2n=36+[2^2n*3^(2n+4)/(2^2n*3^2n)]=
=36+1*3^(2n+4-2n)=36+3^4=36+81=117