2015/87/1-2 (9) — DOI: 10.5486/PMD.2015.7098 — pp. 133-145
Full Text Abstract

Counting invertible sums of squares modulo $n$ and a new generalization of Euler's totient function

Authors: Catalina Calderón, José María Grau, Antonio M. Oller-Marcén and László Tóth

Keywords: quadratic congruence, multiplicative function, Euler's totient function, asymptotic formula

Mathematics Subject Classification: 11A25, 11N37