$1^3 + \dotsb + n^3 = (1 + \dotsb + n)^2$: reason?
15100
Proving the identity $\sum_{k=1}^n {k^3} = \big(\sum_{k=1}^n k\big)^2$ without induction
33633
Re:$ (a,b,c,d)=(pr+qs, qr-ps,pr-qs,ps+qr) $
103572
Does $\sum_{m=1}^{\infty}\sum_{n=1}^{\infty}a_{mn}^3=\sum_{n=1}^{\infty}\sum_{m=1}^{\infty}a_{mn}^3$ occur here?
132081
Geometrical interpretation of $(\sum_{k=1}^n k)^2=\sum_{k=1}^n k^3$
16866
How to Prove $a^3 \cos (B-C) + b^3 \cos (C-A)+ c^3 \cos (A-B)=3abc$?
134311
How to determine equation for $\sum_{k=1}^n k^3$
136868
Prove that $\sqrt{a^2+3b^2}+\sqrt{b^2+3c^2}+\sqrt{c^2+3a^2}\geq6$ if $(a+b+c)^2(a^2+b^2+c^2)=27$
89175
Proof of $(a+b)^{n+1}$
48211
When is $(a+b)^n \equiv a^n+b^n$?
99692
Prove that $a^3+b^3+c^3 \geq a^2b+b^2c+c^2a$
96039
Why is $\frac {1\cdot2\cdot3\cdot...\cdot n}{(n+1)(n+2)...(2n)}\le \frac 1 {n+1}$
142994
How to show $\sum_{i=1}^{n} \binom{i}{2}=\binom{n+1}{3}$?
115976
$\mathbf{Q}[\sqrt 5+\sqrt[3] 2]=\mathbf{Q}[\sqrt 5,\sqrt[3] 2]$?
157087
Can anyone explain why $a^{b^c} = a^{(b^c)} \neq (a^b)^c = a^{(bc)}$
79170
$1 + \frac{1}{1+2}+ \frac{1}{1+2+3}+ ... + \frac{1}{1+2+3+...+n} = ?$
87626
Why are all $n$, s.t. the sum of digits of $n$ and $n^2$ coincide, $\equiv 0,1 \bmod 9$
67666
show that $a^2+b^2+c^2+2abc+3\ge (1+a)(1+b)(1+c)$