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Homework Statement
Prove that there are 3^n ndigit numbers formed with the numbers 4, 5, 6.
The digits can be repeated, e.g.: 444.
Homework Equations

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