Sum of a product with 2 binomial coefficients
25826
Proof of a combinatorial identity: $\sum\limits_{i=0}^n {2i \choose i}{2(n-i)\choose n-i} = 4^n$
134361
Calculating the sum of a binomial coefficient series
39199
closed form for $\binom{n}{0}+\binom{n}{3}+\binom{n}{6}+...+\binom{n}{n}$
133420
Computing the binomial series: $\binom{n}{2}\cdot2^2+\binom{n}{4}\cdot2^4+\binom{n}{6}\cdot2^6+\cdots+ \binom{n}{n}\cdot2^n$
45672
Even/Odd Binomial Coefficients
91458
Sum of the series $\binom{n}{0}-\binom{n-1}{1}+\binom{n-2}{2}-\binom{n-3}{3}+..........$
108688
An identity involving products of sums
142978
combinatorics: sum of product of integer compositions
39957
Product of binomial coefficient as a basis
61270
Binomial Theorem Sum
143365
Is $\sum_{i=1}^{n-1}i=\binom{n}{2}$?
67332
Sum of two squares modulo p
43066
Finding value of $S-T$ in $2$ binomial sum.
96945
General formula of $\sum_{n\ge1}{\binom{2n}{n}^{-k}}$.
279
Sum of two independent binomial variables
64803
Counting two ways, $\sum \binom{n}{k} \binom{m}{n-k} = \binom{n+m}{n}$
110441
Closed form for a formula with a summation over $i\binom{n-i}{k-1}$, and combinatorial proof?