A "fast" way for computing $\sum\limits_{n=1}^{100} n\times 2^n $
7063
How to compute the  formula $\sum  \limits_{r=1}^d r \cdot 2^r$?
72402
Summation of natural number set with power of $m$
146651
Evaluting sum $\sum \limits_{n=0}^\infty\frac{n^k}{n!}$
97266
Summation by parts (finite calculus) of $\sum\limits_{i=0}^{n}i\cdot a^i$
151477
computing the series $\sum_{n=1}^\infty \frac{1}{n^2 2^n}$
6366
Combinatorial proof of summation of $\sum\limits_{k = 0}^n {n \choose k}^2= {2n \choose n}$
83229
Nested summations and their relation to binomial coefficients
145798
Generalizing $\sum \limits_{n=1}^{\infty }n^{2}/x^{n}$ to $\sum \limits_{n=1}^{\infty }n^{p}/x^{n}$
15031
Convergence test of the series $\sum\sin100n$
92784
Intuitive (combinatorial) proof of $2^n=\sum_{k=0}^n {n\choose k}$
61749
Limit of the infinite sum of $\frac{n}{2^n}$?
121554
Finding $\sum\frac{1}{2^n(n+1)}$
22696
Faster ways to calculate frequencies and cast from long to wide
123675
Evaluate the following limit of finite sum
116722
Simplifying $\big(\sum_{i=0}^n\binom{k}{i}\binom{M-k}{n-i}\frac{k-i}{M-n}\big)/{\binom{M}{n}}$
5054
Calculate $\sum\limits_{k=0}^{\infty}\frac{1}{{2k \choose k}}$
156814
Compute the limit of the sequence ${\textstyle\sum_{k=1}^n}\frac1{\sqrt{n^2+k}}$