Find the nth term of a sequence whose first several terms are given: 1/3, 4/5, 9/7, 16/9...

Your sequence could be:

 

1/3, 4/5, 9/7, 16/9, 25/11, 36/13, 49/15, 64/17, 81/19, 100/21, 121/23, 144/25, 169/27.........etc.

 

The "closed form" of the sequence could be:

 

a(n) = n^2/(2 n + 1) (for any term)