Square-free values of
arXiv:1010.6217
Abstract
We show that there is a positive constant such that \[\sum_{n\le x}μ^2(n^2+1)c_0x+O_{\varepsilon}(x^{7/12+\varepsilon})\] for any fixed . This improves a result of Estermann [3] from 1931, in which the error term had an exponent 2/3. The proof involves counting rational points near an algebraic curve, which is done via the "determinant method."
A small correction has been made in the final section