Question

I need it as a linear function thank you

Answer 1

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

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