Find the sums of the series (combinatorial series)
18793
Partial sum of rows of Pascal's triangle
43903
Find the sum for $\sum_{n=1}^{\infty}(-1)^{(n+1)}\frac{2n+1}{3^n} $
148143
Find the sum to n terms as well as the sum to infinity of the series:
7177
Find sum of series $ \sum_{n=1}^{\infty} (n\cdot \ln \frac{2n+1}{2n-1} - 1) $
57986
Sum of products of combinatorials
27001
How to calculate the following sum:
33104
Combinatorial Proof with Summation Identity
92754
Closed form for the series: $\sum_{n=1}^{\infty}x^{n^2}$
14883
Find $\sum_{n=1}^{\infty}$ $\frac{n^{2}}{\left(n+1\right)\left(n+2\right)\left(n+3\right)\left(n+4\right)}$
98082
Another combinatorics problem: $\sum\limits_{k = 0}^n (-1)^k \binom{2n-k}k2^{2n-2k}=2n+1$
125148
Summation of series $\sum_{k=0}^\infty 2^k/\binom{2k+1}{k}$
71824
Finding the sum of the series $\frac{1}{1!}+\frac{1+2}{2!}+\frac{1+2+3}{3!}+ \ldots$
60860
Combinatorial proof of $\sum_{i = 0}^{n} \binom{i}{r - 1} = \binom{n + 1}{r}$ and then use result to find a formula for $1^2 + 2^2 + \ldots + n^2$
104078
Calculate the sum of the infinite series $\sum_{n=0}^{\infty} \frac{n}{4^n}$
32637
What is the sum of this series: $\displaystyle\sum_{n=0}^{\infty} \dfrac{a^n}{(3n)!}$
65653
Find a closed form of the series $\sum_{n=0}^{\infty} n^2x^n$
94943
Sum of series with addition: $\sum_{n=1}^\infty \frac{1}{n^2(n+1)}$