Respuesta :

[tex]5~~,~~\stackrel{5(6)}{30}~~,~~\stackrel{30(6)}{180}~~,~~\stackrel{180(6)}{1080}~~,~~\stackrel{1080(6)}{6480}~\hfill \boxed{f(x)=x_{n-1}(6)}[/tex]

now, that's recursive, we can also write it in explicit as [tex]5(6)^x[/tex]