How to solve in integers the equation $$y^k=x^2+x$$ where $k\ge 2, k \in \mathbb N$.
My work so far
1) $x^2+x=x(x+1)$. But $\gcd(x,x+1)=1$
Then $$y\cdot y\cdot...\cdot y=x(x+1)$$
2) If $k=2n$. Then $$y^k=x(x+1)$$ $$\left(y^n\right)^2=x(x+1)$$ Then $x=m^2, x+1=l^2$. Impossible
3) If $n=2k+1$.
I need help here
Hint: both $x$ and $x+1$ must be $k$'th powers.