Find a formula for the sum of the $n$ terms of the sequence (Summations & Sequences)
2678
Values of $\sum_{n=0}^\infty x^n$ and $\sum_{n=0}^N x^n$
115170
What is the formula for this numerical series?
17056
How to find answer to the sum of series $\sum_{n=1}^{\infty}\frac{n}{2^n} $
86900
Formula for the $1\cdot 2 + 2\cdot 3 + 3\cdot 4+\ldots + n\cdot (n+1)$ sum
107976
Find a closed formula for $\sum_{n=1}^\infty nx^{n-1}$
141978
How to find the infinite sum
44577
Finding a formula to sum natural numbers up to $n$
22657
How to find the sum of the infinite series?
110975
Summation of reciprocals
128200
Sequence sum question: $\sum_{n=0}^{\infty}nk^n$
36361
How to calculate the summation $(\sum_{p = k}^{n} \binom{n}{p}) / 2^n$ quickly?
14883
Find $\sum_{n=1}^{\infty}$ $\frac{n^{2}}{\left(n+1\right)\left(n+2\right)\left(n+3\right)\left(n+4\right)}$
113713
Closed formula for the sum of the following series
44111
Find the value of $\sum_{k=1}^{n}k\binom{n}{k}$?
75367
Find a simple formula for $\binom{n}{0}\binom{n}{1}+\binom{n}{1}\binom{n}{2}+...+\binom{n}{n-1}\binom{n}{n}$
158004
A formula for $1^4+2^4+...+n^4$
124135
A general formula for $\sum (k-1)(k-2)(k-3)$?