How to calculate the sum of the squares of the reciprocals of the first n positive integers
39659
Is there a closed formula for this summation?
93657
Proving “The sum of $n$ consecutive cubes is equal to the square of the sum of the first $n$ numbers.”
110975
Summation of reciprocals
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 $1^2 + 2^2 + \ldots + n^2$
116360
Sum of n-th roots of unity
64581
How to find the sum $\sum\limits_{k=1}^n (k^2+k+1)k!$?
126105
Compute $\sum_{k=1}^{n} \frac 1 {k(k + 1)} $
94060
Sum of square binomial coefficients
42831
How to derive the formula for the sum of the first $n$ odd numbers: $n^2=\sum_{k=1}^n(2k-1).$
1379
Summation of $n^2x^n$ terms
27001
How to calculate the following sum:
140433
The number of ways of writing an integer as a sum of two squares
123427
Proving the sum of the first $n$ natural numbers by induction
5332
Find the value of $\sum_0^n \binom{n}{k} (-1)^k \frac{1}{k+1}$
67899
Integer squares of the form $x^4+x^3+x^2+x+1$
36694
Sum of first n natural numbers proof
106280
Integrating the formula for the sum of the first $n$ natural numbers