Question 15
Find the number of strictly increasing sequences of nonnegative integers with the following properties:
- The first term is $0$ and the last term is $12$. In particular, the sequence has at least two terms.
- Among any two consecutive terms, exactly one of them is even.
- The first term is $0$ and the last term is $12$. In particular, the sequence has at least two terms.
- Among any two consecutive terms, exactly one of them is even.