A binary quadratic Titchmarsh divisor problem. (English) Zbl 1475.11174
Let \(\tau(n)=\sum_{d|n} 1\) be the divisor function. As a quadratic analogue of the Titchmarsh problem, in the paper under review, the author proves that for \(N\) large enough
\[
\sum_{p^2+q^2\leq N}\tau(p^2+q^2+1)=C\,\frac{N}{\log N}\left(1+O\left(\frac{\log\log N}{\log N}\right)\right),
\]
where \(p,q\) are primes and the constant \(C\) is given by
\[
C=\frac{\pi}{4}\prod_{p>2}\left(1-\frac{1+3p(\frac{-1}{p})}{p(p-1)^2}\right).
\]
Reviewer: Mehdi Hassani (Zanjan)
MSC:
11N37 | Asymptotic results on arithmetic functions |
11N36 | Applications of sieve methods |
11L07 | Estimates on exponential sums |
11L20 | Sums over primes |