T(n) means that whatever term you want it can be put in anywhere you see an n.
T(1) means
T(1) = 1 - 3*1
T(1) = 1 - 3
T(1) = - 2
The second term would be
T(2) = 1 - 3*2
T(2) = 1 - 6
T(2) = -5
The third term (the one you want)
T(3) = 1 - 3*3
T(3) = 1 - 9
T(3) = - 8
