If f (1) = 3 and f (n) = - 2f (n-1) + 1 what is f (4)

If f (1) = 1 then f (f (1)) = 1 but f (f (1)) = 3, so f (1) isn't equal to 1If f (1) >2 then f (2) >3, so f (f (1)) >3, but f (f (1)) = 3, so f (1) isn't greater than 2Thus f (1) = 2, and f (2) = 3f (3) = f (f (2)) = 6, and f (6) = f (f (3)) = 9, so 9 > f (5) > f (4) > 6, so f (5) = 8 and f (4) = 7.