Combinatorial proof of a binomial identiity
125174
Combinatorial intuition of identity
41726
Musical and combinatorial proof
45460
Proof verification of a number theory problem involving sequences.
107964
Simple combinatorics problem.
34299
Combinatorial proof of $\sum_{k=0}^n k \cdot k! = (n+1)! -1$
10875
proof of binomial identity involving double sum
122006
Proving combinatorial identity $\sum_{k=0}^{n}(-1)^k \binom{2n-k}k 2^{2n-2k} = 2n+1$ "directly"
59831
How to relate combinatorial proof to bipartite graphs?
3786
Help finding a combinatorial proof of $k {n \choose k } = n {n - 1 \choose k -1}\;$
97254
What is the proof of permutations of similar objects?
103504
Weird $3^n$ in an identity to be combinatorially proved
19571
Combinatorial proof for $\sum_{k = 0}^n \binom {r+k} k = \binom {r + n + 1} n$
87320
Proving identities like $\sum_{k=1}^nk{n\choose k}^2=n{2n-1\choose n}$ combinatorially
111954
Computing the cardinality of a combinatorial set
133181
Hint on how to prove the identity $\sum_{0 \leq k \leq n } \binom{k}{m} = \binom{n + 1}{m + 1}$
74887
Combinatorial proof of the identity ${n+1\choose k+1}={k\choose k}+{k+1\choose k}+...+{n-1\choose k}+{n\choose k}$
109648
Proving an identity for Bernoulli polynomials