Finite groups with specific number of cyclic subgroups

Abstract

In this note, we classify all finite groups having exactly 6, 7 or 8 cyclic subgroups. This gives a partial answer to the open problem posed by Tarnauceanu (Amer. Math. Monthly, 122 (2015), 275-276). As a consequence of our results, we also obtain an important result concerning with the converse of Lagrange's theorem.

Statement of the Theorem 3.5 has been changed