Question 20
For how many pairs of sequences of nonnegative integers $\left(b_{1}, b_{2}, \ldots, b_{2018}\right)$ and $\left(c_{1}, c_{2}, \ldots, c_{2018}\right)$ does there exist a sequence of nonnegative integers $\left(a_{0}, \ldots, a_{2018}\right)$ with the following properties:
- For $0 \leq i \leq 2018, a_{i}\lt 2^{2018}$;
- For $1 \leq i \leq 2018, b_{i}=a_{i-1}+a_{i}$ and $c_{i}=a_{i-1} \mid a_{i}$;
where $\mid$ denotes the bitwise or operation?
(The bitwise or of two nonnegative integers $x=\cdots x_{3} x_{2} x_{1} x_{0}$ and $y=\cdots y_{3} y_{2} y_{1} y_{0}$ expressed in binary is defined as $x \mid y=\cdots z_{3} z_{2} z_{1} z_{0}$, where $z_{i}=1$ if at least one of $x_{i}$ and $y_{i}$ is 1 , and 0 otherwise.)
- For $0 \leq i \leq 2018, a_{i}\lt 2^{2018}$;
- For $1 \leq i \leq 2018, b_{i}=a_{i-1}+a_{i}$ and $c_{i}=a_{i-1} \mid a_{i}$;
where $\mid$ denotes the bitwise or operation?
(The bitwise or of two nonnegative integers $x=\cdots x_{3} x_{2} x_{1} x_{0}$ and $y=\cdots y_{3} y_{2} y_{1} y_{0}$ expressed in binary is defined as $x \mid y=\cdots z_{3} z_{2} z_{1} z_{0}$, where $z_{i}=1$ if at least one of $x_{i}$ and $y_{i}$ is 1 , and 0 otherwise.)