On Thu, Sep 23, 2010 at 8:48 PM, zak seidov <zakseidov at yahoo.com> wrote: > 1. a(n) = 10^n-th odd squarefree number > 3. a(n)/10^n at n->oo = > (Pi/2)^2 = 2.4674011002723? This follows from the formula given in oeis.org/classic/A056911 : A056911(n) = n * (3/2) * zeta(2) + O(n^(1/2)) = n * (3/2) * (pi^2 / 6) + O(n^(1/2)) Maximilian