In this short note, we treat an unbalanced shifted convolution sum of Fourier coefficients of cusp forms by a rather simple argument. Our result improves previous results established by more advanced approaches.
Estimates of Fourier coefficients of cusp forms associated to cofinite Fuchsian subgroups
Oscillatory behavior and equidistribution of signs of Fourier coefficients of cusp forms
Landau and Ramanujan approximations for divisor sums and coefficients of cusp forms
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