Published online by Cambridge University Press: 02 June 2015
Let $\{{\it\phi}_{j}(z):j\geq 1\}$ be an orthonormal basis of Hecke–Maass cusp forms with Laplace eigenvalue
$1/4+t_{j}^{2}$. Let
${\it\lambda}_{j}(n)$ be the
$n$th Fourier coefficient of
${\it\phi}_{j}$ and
$d_{3}(n)$ the divisor function of order three. In this paper, by the circle method and the Voronoi summation formula, the average value of the shifted convolution sum for
$d_{3}(n)$ and
${\it\lambda}_{j}(n)$ is considered, leading to the estimate
$$\begin{eqnarray}\displaystyle \mathop{\sum }_{n\leq X}d_{3}(n){\it\lambda}_{j}(n-1)\ll X^{29/30+{\it\varepsilon}}, & & \displaystyle \nonumber\end{eqnarray}$$
$t_{j}$ and
${\it\varepsilon}$.