What is the term for a factorial type operation, but with summation instead of products?
2675
Proof $1+2+3+4+\cdots+n = \frac{n\times(n+1)}2$
155150
Division of Factorials [binomal coefficients are integers]
33559
Product or sum of invertible matrix give an invertible matrix?
146305
Simplify sum of factorials with mathematical induction
125981
Closed-Form Solution to Infinite Sum
74149
Reducing an indicator function summation into a simpler form.
76892
Factoring inequalities on Double Summation (Donald Knuth's Concrete Mathematics)
120913
How would you write a non-recursive algorithm to calculate factorials?
36920
Universal factoring method or list of methods (trinomials)
68481
Finite Summation of Fractional Factorial Series
73242
Simplify vector expression - is there something like "Factor" for vectors, dot products etc.?
133073
Evaluating series with factorial denominator (sanity check).
14540
Any shortcut to calculate factorial of a number (Without calculator or n to 1)?
47753
Closed form of series with factorial-squared denominator?
118387
How to extend summations to fractional orders?
17213
what operation repeated $n$ times results in the addition operator?
96895
Mathematical notation for a conditional sum