It's true that $(n) (n + 1) (2n + 1)$ is a multiple of 6?
50670
Use Mathematical Induction to prove 6 divides $n(n+1)(2n+1)$
20271
Proving $\sum_{k=1}^n{k^2}=\frac{n(n+1)(2n+1)}{6}$ without induction
136580
Proving $\sum_{k=0}^n\binom{2n}{2k} = 2^{2n-1}$
132879
Matlab questions about $a_{n+1} = 4a_{n} + n +1$
97656
Finding $a_n$ if $a_0=a_1=1,a_{n+1}=n(a_n+a_{n-1})\ \ (n\ge 1).$
118372
Combination proof for $n(n+1)2^{n-2}=\sum_{k=1}^{n}k^2\binom{n}{k}$
15210
Group of order 6 proof
16472
Sum of First $n$ Squares Equals $\frac{n(n+1)(2n+1)}{6}$
143365
Is $\sum_{i=1}^{n-1}i=\binom{n}{2}$?
2425
Is that true that all the prime numbers are of the form $6m \pm 1$?
118197
Solve $n(n+1)(n+2)=6m^3$ in positive integers
92737
primes whose difference is a multiple of $n$
126888
How can you show that $\binom {n}{7}=\sum_{k=7}^n \binom {k-1} {6}$?
80365
Prove that $n$ is divisible by $6$
108497
Can $2^n$ and $2^{n+1}$ have the same digit sum?
83738
Prove $(k,n+k)=1$ iff $(k,n)=1$
158508
Combinatorial Proof for Binomial Identity: $\sum_{k = 0}^n \binom{k}{p} = \binom{n+1}{p+1}$