The sequence is
n-2
-------
n^2
To write the first three terms of this sequence, use n = 1, n = 2, n = 3:
1-2 -1
------ = ----- = -1 (first term)
1^2 1
2-2
----- = 0 (second term)
2^2
3-2
------ = 1/9 (third term)
3^2