求证：
∑i=1⌈n2⌉Cn2i−1=∑i=0⌊n2⌋Cn2i \sum _ {i = 1} ^ {\lceil \frac{n}{2} \rceil} C _ n ^ {2i-1} = \sum _ {i=0} ^ {\lfloor \frac {n}{2} \rfloor} C _ n ^ {2i}∑i=1⌈2n⌉Cn2i−1=∑i=0⌊2n⌋Cn2i
