Diophantine approximation with one prime of the form $p=x^2+y^2+1$

Abstract

Let $\varepsilon>0$ be a small constant. In the present paper we prove that whenever $\eta$ is real and constants $\lambda _i$ satisfy some necessary conditions, then there exist infinitely many prime triples $p_1,\, p_2,\, p_3$ satisfying the inequality \begin{equation*} |\lambda _1p_1 + \lambda _2p_2 + \lambda _3p_3+\eta|<\varepsilon \end{equation*} and such that $p_3=x^2 + y^2 +1$.