Summation $\sum_{j=2}^{n-1}j^2$ Properties
16472
Sum of First $n$ Squares Equals $\frac{n(n+1)(2n+1)}{6}$
107433
Prove the sum to n terms of the series
132182
$\sum_{n=1}^\infty \sum_{m=1}^\infty\frac{1}{(m+n)^2}$
94943
Sum of series with addition: $\sum_{n=1}^\infty \frac{1}{n^2(n+1)}$
67752
Show that $\sum_{n = 1}^{+\infty} \frac{n}{2^n} = 2$
16776
How to prove $\sum_{m=1}^\infty \sum_{n=1}^\infty \frac{1}{m^2+n^2}=+\infty$
110441
Closed form for a formula with a summation over $i\binom{n-i}{k-1}$, and combinatorial proof?
129801
Finding a closed form for $\sum^{n}_{k=1} \frac{k}{(k+1)!} $
85626
prove $\sum_{i=1}^{n}(x_i-\bar{x})^2\lt\sum_{i=1}^{n}(x_i-a)^2$
34386
Sum of a complex, finite geometric series and its identity
92810
What is $\sum_{r=1}^\infty\frac{r+2}{2^{r+1}(r)(r+1)}$?
73258
Power series summation
143365
Is $\sum_{i=1}^{n-1}i=\binom{n}{2}$?
83400
Sum of products of binomial coefficients: $ \sum_{l=0}^{n-j} \binom{M-1+l}{l} \binom{n-M-l}{n-j-l} = \binom{n}{j} $
67271
$\sum_{n=-\infty}^{\infty}\frac{1}{(u +n)^2}=\frac{\pi^2}{(\sin \pi u)^2}$
127047
How to show that $\sum_{i=1}^n | \langle f, f_i\rangle |^2 \leq \Vert f \Vert^2$
138313
How to sum $\sum_{n=1}^{\infty} \frac{1}{n^2 + a^2}$?