摘要: 性质 \[\begin{aligned} f(n) & =\sum_{i=0}^{n}\binom{n-i}{i} \\ & =\sum_{i=0}^{n}\binom{n-i-1}{i-1}+\sum_{i=0}^{n}\binom{n-i-1}{i} \\ & =\sum_{i=0}^{n-1} 阅读全文
posted @ 2025-07-25 20:27 TangyixiaoQAQ 阅读(41) 评论(0) 推荐(0)