How to find closed formula for the sum of the first n odd perfect squares?
111298
Direct Proof that $1 + 3 + 5 + \cdots+ (2n - 1) = n\cdot n$
65653
Find a closed form of the series $\sum_{n=0}^{\infty} n^2x^n$
69084
What is the closed form for $\sum_{n=1}^\infty \frac1n - \frac1{n+1/p}$?
146746
A formula for the sum of the triangular numbers?
54355
$1+x+\ldots+x^n$ perfect square
136066
Find the sum $\sum _{n=1}^{\infty }\left(\sqrt{n+2}-2\sqrt{n+1}+\sqrt{n}\right)$
39199
closed form for $\binom{n}{0}+\binom{n}{3}+\binom{n}{6}+...+\binom{n}{n}$
137109
Evaluating a summation of inverse squares over odd indices
35525
Methods to compute $\sum_{k=1}^nk^p$ without Faulhaber's formula
16472
Sum of First $n$ Squares Equals $\frac{n(n+1)(2n+1)}{6}$
119606
Closed form of summation
5448
Finding the closure of some subsets of the ordered square
87479
Closed form for $\sum_{k=0}^{n-p}\binom{n}{k}\binom{n}{p+k}$
38741
Finding a general formula for summation
127150
Finding general formula of $\sum_{i=0}^n i^2 \binom{n}{i}$
146581
The sum of the first $n$ squares $(1 + 4 + 9 + \cdots + n^2)$ is $\frac{n(n+1)(2n+1)}{6}$
18461
Sum of odd Fibonacci Numbers