Simplify Summation of combination
86426
calculate $\sum_{1\le i\le r}\frac{i+1} { r+1}{2r-i\choose r-i}{s+i-2\choose i}+\frac{1}{r+1}{2r\choose r}$?
83229
Nested summations and their relation to binomial coefficients
100314
Problem with the subscripts of adjacent sums
103347
combinatorial proof of summation
57793
Compile nested Sums
146274
Fastest way to do this double summation?
94836
Total combinations from number of unique combination?
137973
What is the formula for Combination with repetition?
44649
Summing a series having a geometric component
157280
How do I sum up specific things in Numbers?
75457
How do i simplify the following: $\sum_{i=1}^n (3i^2+4) - \sum_{j=2}^{n+1} (3j^2+1)$
78622
How to understand the combination formula?
155367
summation of multiplying series with negative terms
74315
Constraint on variables in summation
115213
How to simplify $\sqrt[3]{7+5\sqrt{2}}+\sqrt[3]{7-5\sqrt{2}}$
45588
Summing a series with a changing power
102816
multiplication equivalent of the summation symbol