OFFSET
1,2
EXAMPLE
{4r+1r}=0.09...; {4r-1r}=0.85...;
{4r+2r}=0.70...; {4r-2r}=0.23...;
{4r+3r}=0.32...; {4r-3r}=0.61...;
{4r+4r}=0.94...; {4r-4r}=0.00...;
so that a(4)=2.
MATHEMATICA
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Sep 03 2011
STATUS
approved