polynomial o f degree 3n

P (x) is a polynomial o f degree 3n such that
P(0) = P ( 3 ) = ..... = P(3n) = 2;
P ( I ) = P ( 4 ) = .............. = P ( 3 n - 2) = 1;
P ( 2 ) = P ( 5 ) = .................. = P ( 3n - l ) = 0;
and   P(3n + I ) = 730.
Determine n.