Combinations proving problem
37569
Prove that $\binom{n}{r} + \binom{n}{r+1} = \binom{n+1}{r+1} $
158141
Getting all the combinations in an array
115435
Induction: prove using congruences
90904
Combinatorial proof of an identity with squared binomial coefficients
127311
Challenging probability problem
113290
Prove combinatorics identity
76368
Proving the Binomial theorem
15349
Combinatorics riddle: keys and a safe
54880
algorithm that will take numbers or words and find all possible combinations
114277
Proving in Discrete Structures Problem that $2^N = \binom{N}{0} + \binom{N}{1} + \binom{N}{2} + \dots + \binom{N}{N}$
78359
Induction and Recursion Proof using Catalan Numbers
143573
Problem (1.8) A Path to Combinatorics Solution Verification.
65843
Number of possible combinations of x numbers that sum to y
14979
Making all possible combinations of a list
4610
Proving an identity with a combinatorial proof: $\binom{n}{k}\binom{k}{r}=\binom{n}{r}\binom{n-r}{k-r}$
61483
Prove the following identity combinatorially
87664
Combination of $n$ letter out of $3n$.