Question

let circle C with radius r,and there are enough much unit circles ,now put these unit circle into the large circle C such that these circles cannot intersect in the large ,ask what is the maximum number of the unit circles which is putted into the large circle .let this maximum number is M(r),we can prove the M(1)=1，M(2)=2,M(3)=7,but the r belong to positive real numbers,so we define R(n)=the minimize radius of the large circle which load n unit circles,so we have if R(n）