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摘要: (默认 $n \le m$) 设: $$ F_k = \lfloor \frac n k \rfloor \times \lfloor \frac m k \rfloor = \sum_{k|d} f_d $$ $$ f_k = \sum_{k|d} \mu_{\frac d k} \times F 阅读全文
posted @ 2022-09-24 11:10 Chy12321 阅读(18) 评论(0) 推荐(0) 编辑