随笔分类 - 数学-斯特林数
摘要：$$\begin &\sum_n ik \binom \left(\frac{1}\right)i \left(\frac\right) \ =&\frac{1}{mn}\sum_n ik \binom(m-1) \ =&\frac{1}{mn}\sum_n \sum_k (m-1)\binom\b
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摘要：$$\begin &\sum_^n\sum_i \begini\j\end2j j! \ =&\sum_^n\sum_n \begini\j\end2j j! \ =& \sum_^n \sum_n 2jj! \frac{1}{j!} \sum_^j (-1)^k \binom (j-k)^i \
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摘要：$$\begin &\sum_n f(k) xk \binom \ =&\sum_m a_i\sum_n ki xk \binom \ =&\sum_^m a_i\sum_nxk \binom \sum_^i \binom \begini \ j\endj! \ =&\sum_m a_i \sum_
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