cp's OEIS Frontend

Denoting the number of squarefrees up to n by Q(n), we say (n, Q(n)) is on the upper convex hull of the squarefree number graph if for all integers m_1 < n and all integers m_2 > n, (n, Q(n)) is above the secant line from (m_1, Q(m_1)) to (m_2, Q(m_2)). To determine whether n is the index of a vertex in the upper convex hull, it suffices to only check the record maximum points of Q(m)-6*m/Pi^2.

The sequence contains each squarefree integer k where Q(k) - 6*k/Pi^2 is smaller than Q(m) - 6*m/Pi^2 for any 0 < m < k. Where both m and k are squarefree. It is well known that Q(k) is asymptotic to 6*k/Pi^2.