On the fourth moment in the Rankin-Selberg problem

Aleksandar Ivić

If $$\Delta (x):=\sum _{n\le x}{c}_n-Cx$$ denotes the error term in the classical Rankin-Selberg problem, then it is proved that $$ \int_0^X Δ^4(x)\d x \ll_εX^{3+ε},\quad \int_0^X Δ_1…