Is there a pattern to expression for the nested sums of the first $n$ terms of an expression?
70677
Finite Sum of Power?
96895
Mathematical notation for a conditional sum
133070
Finding a closed form expression for the recurrence relation $a(n,k+1)=(k+1)^n+\sum_{m=1}^k {k+1\choose m}a(n,m)$
110441
Closed form for a formula with a summation over $i\binom{n-i}{k-1}$, and combinatorial proof?
139307
Closed form expression for infinite series
68725
Find expression for : $ S_n =\sum_{i=1}^{n} \frac{i}{i^4+i^2+1} $
19790
How to deal with recursion formula in Mathematica?
125981
Closed-Form Solution to Infinite Sum
8806
Summation of binomial coefficients
48200
Simplify $\sum_{i=0}^n (i+1)\binom ni$
23726
A closed form for $1^{2}-2^{2}+3^{2}-4^{2}+ \cdots + (-1)^{n-1}n^{2}$
22840
The sum of the first $n$ squares is a square: a system of two Pell-type-equations
44577
Finding a formula to sum natural numbers up to $n$
84159
The sum to n terms of the series $\frac{1}{\sqrt 1+\sqrt 3} + \frac{1}{\sqrt 3 +\sqrt 5} ....$
65648
Different ways to come up with $1+2+3+\cdots +n=\frac{n(n+1)}{2}$
86900
Formula for the $1\cdot 2 + 2\cdot 3 + 3\cdot 4+\ldots + n\cdot (n+1)$ sum
39909
Getting a closed form from $\sum_{i=1}^{n-1} \sum_{j=i+1}^{n} \sum_{k=1}^{j} 1$