Find the next term of the series Z1, X4, V9, T16, ?

Explanation

1. 01

   Letters: Z, X, V, T go back 2 each time, so the next is R.

2. 02

   Numbers: 1, 4, 9, 16 are $1^2, 2^2, 3^2, 4^2$, so the next is $5^2 = 25$.

3. 03

   The next term is R25.