For a sequence defined by f (1) = 13 and 2f (n-1) + (n-2), which of the following is the value of f (4)

(1) 53

(2) 76

(3) 108

(4) 126

Given that:

f (1) = 13 and 2f (n-1) + (n-2)

then:

f (4) will be found as follows:

f (2) = 2f (2-1) = 2f (1) = 2*13=26

f (3) = 2f (3-1) + (3-2) = 2f (2) + 1=2*26+1=53

f (4) = 2f (4-1) + (4-2) = 2f (3) + (4-2) = 2 (53) + 2=108

Thus:

Answer: (3) 108