Where does the summation formula $(c^n - 1)/(c -1)$ come up? What does it apply to?
2678
Values of $\sum_{n=0}^\infty x^n$ and $\sum_{n=0}^N x^n$
104646
Question on simplification of $\sum_{n=1}^{\infty}\frac{2}{(2n+1)(2n+3)}$?
36361
How to calculate the summation $(\sum_{p = k}^{n} \binom{n}{p}) / 2^n$ quickly?
147795
$\sum x_n^2$ and $\sum y_n^2$ converge, what does $\sum (x_n + y_n)^2$ do?
89771
$\frac{1}{s-1}+\sum_{n=1}^{\infty}\left[\frac{1}{n^s}+\frac{1}{s-1}\left(\frac{1}{(n+1)^{s-1}} - \frac{1}{n^{s-1}}\right)\right]$
150642
How to prove $\sum^n_{i=1} \frac{1}{i(i+1)} = \frac{n}{n+1}$?
54753
What does $\sum_{i=1}^{10} 2$ mean exactly?
12423
"Closed" form for $\sum \frac{1}{n^n}$
120743
For Riemann sums involving square roots, why do we let $c_{i} = \frac{i^{2}}{ n^{2}}$?
1379
Summation of $n^2x^n$ terms
134311
How to determine equation for $\sum_{k=1}^n k^3$
59208
How to explain the equation about summation?
50050
A formula for the power sums: $1^n+2^n+\dotsc +k^n=\,$?
69045
Solving this summation: $\sum_{i=1}^k i\cdot2^i$
120988
Infinite Series $\sum 1/(n(n+1))$
77519
I'm searching for the formula of the series $ \sum_{n=0}^{\infty}a^{n^l} $
39659
Is there a closed formula for this summation?