Prove that there are 3^n n-digit numbers formed with the numbers 4, 5, 6.
The digits can be repeated, e.g.: 444.
The Attempt at a Solution
What I thought was to prove it by induction. So [itex]P[/itex](1) is true, because we have only 4, 5, 6.
But it seems to me unreasonable to say [itex]P[/itex](k)[itex] => P[/itex](k+1)
any help is appreciated