Is there any closed form for $\sum_{k=0}^n\frac{x^k}{k!}$?
42736
Is there a closed form for $\sum_{k=0}^n \frac{x^k}{k!}$?
110441
Closed form for a formula with a summation over $i\binom{n-i}{k-1}$, and combinatorial proof?
137155
Sum $ \sum\limits_{k=1}^{\infty} \frac{k^2}{2^k}$
118436
Identifying the series $\sum\limits_{k=-\infty}^{\infty} 2^k x^{2^k}$
116987
Finding the radius of convergence for $\sum_{n=0}^{\infty} \frac{(n!)^kx^n}{(kn)!}$
39659
Is there a closed formula for this summation?
14239
How to show $\sum_{k=0}^{n}\binom{n+k}{k}\frac{1}{2^k}=2^{n}$
23726
A closed form for $1^{2}-2^{2}+3^{2}-4^{2}+ \cdots + (-1)^{n-1}n^{2}$
5272
Proving that $\sum_{k=0}^{n}\frac{(-1)^k}{{n\choose k}}=[1+(-1)^n] \frac{n+1}{n+2}.$
64581
How to find the sum $\sum\limits_{k=1}^n (k^2+k+1)k!$?
140462
Find a closed form for the power series $f_p(x)=\sum\limits_{n=0}^\infty\frac{n^p}{n!}x^n$
146651
Evaluting sum $\sum \limits_{n=0}^\infty\frac{n^k}{n!}$
37007
Evaluating $\sum_{k=1}^{n} \frac{1}{k(k+1)}$
30518
Formula for $\sum_{k=1}^n \frac{1}{k(k+1)(k+2)}$?
106552
Find the sum of $\sum \frac{1}{k^2 - a^2}$ when $0<a<1$
3356
Why $\sum_{k=0}^m x^k $ is equal to $\dfrac{x^{m+1}-1}{x-1} $?
37148
How to evaluate $ \lim \limits_{n\to \infty} \sum \limits_ {k=1}^n \frac{k^n}{n^n}$?