Help finding the sum $\sum_{n=1}^{\infty} \frac{n^2+1}{5^n}$
7686
How to prove $\sum_{n=0}^{\infty} \frac{n^2}{2^n} = 6$?
135927
Calculating $\sum_{n=1}^\infty\frac{1}{(n-1)!(n+1)}$
54661
How to find the sum $\sum\limits_{n=1}^{\infty}\frac{1}{n!(n^4+n^2+1)}$
158737
What is the value of the series $\sum\limits_{n=1}^\infty \frac{(-1)^n}{n^2}$?
58262
Find the sum of the series $1+\frac{1}{3}\cdot\frac{1}{4}+\frac{1}{5}\cdot\frac{1}{4^2}+\frac{1}{7}\cdot\frac{1}{4^3}+\cdots$
16143
How can I prove that $\sum_{n=1}^\infty \frac{1}{n(n+1)} = 1$?
117863
Series $\sum_{n=1}^\infty \frac{n^n}{(n!)^2}$
127189
sum of this series: $\sum_{n=1}^{\infty}\frac{1}{4n^2-1}$
9124
Find the exact value of the infinite sum $\sum_{n=1}^\infty \big\{\mathrm{e}-\big(1+\frac1n\big)^{n}\big\}$
62913
Understanding $\sum_{n=1}^{\infty} \frac{1}{n^4} = \frac{\pi^4}{90}$
134610
Find the sum of finite series $S=\sum_{k=1}^{2015}{(-1)^{\frac{k(k+1)}{2}}}k$
89771
$\frac{1}{s-1}+\sum_{n=1}^{\infty}\left[\frac{1}{n^s}+\frac{1}{s-1}\left(\frac{1}{(n+1)^{s-1}} - \frac{1}{n^{s-1}}\right)\right]$
26446
Find the sum : $\displaystyle\sum_{i=0}^n \frac{2^i}{1+x^{2^{i}}}$
25395
Sum $\sum_{n=1}^\infty \frac{n^2}{(n+2)!}$
67752
Show that $\sum_{n = 1}^{+\infty} \frac{n}{2^n} = 2$
152227
How to sum this series to infinity: $\sum_{n=0}^{\infty} \frac1{2^{2^n}}$
32866
How find this sum $\sum\limits_{n=0}^{\infty}\frac{1}{(3n+1)(3n+2)(3n+3)}$