I am trying to figure this out.

I have used . to denote subscript.

A sequence h.0,h.1,h.2,... is defined as h.0=1, h.1=2, h.2=3

h.k= h.k-1 + h.k-2 + h.k-3

show h.n <= 3^n

I have it to the point where h.k+1 = h.k + h.k-1 + h.k-2

= 3^k + h.k-1 + h.k-2

but once again am stuck as to what to do.

Any help muchly appreciated