Is there a closed form expression for the sum of the reciprocal values of the first n natural numbers?
10357
Do harmonic numbers have a “closed-form” expression?
18402
Sum of the reciprocals of divisors of a perfect number is $2$?
42736
Is there a closed form for $\sum_{k=0}^n \frac{x^k}{k!}$?
22077
Closed form for the sequence defined by $a_0=1$ and $a_{n+1} = a_n + a_n^{-1}$
36694
Sum of first n natural numbers proof
23726
A closed form for $1^{2}-2^{2}+3^{2}-4^{2}+ \cdots + (-1)^{n-1}n^{2}$
22441
Does the sum of reciprocals of primes converge?
115236
Calculate the sum of inverse values of ${n\choose 0}, {n\choose 1}, ... {n\choose n}$
58972
Proof/Derivation of Closed form of Binomial Expression $\sum\limits_{k=0}^{2n}(-1)^k\binom{2n}{k}^2$
58264
How to derive the formula for the sum of the first $n$ perfect squares?
49982
Closed expression for infinite series
45392
Every natural number can be written as the sum of distinct Fibonacci numbers?
62792
Can sum of a rational number and its reciprocal be an integer?
92754
Closed form for the series: $\sum_{n=1}^{\infty}x^{n^2}$
57759
Determining the infinite sum $\sum\limits_{n=0}^{\infty}\frac{(-1)^n}{2n+1}$
44577
Finding a formula to sum natural numbers up to $n$
139307
Closed form expression for infinite series