Distances in a bee's honeycomb (noch nicht übersetzt)
Problem 354
Consider a honey bee's honeycomb where each cell is a perfect regular hexagon with side length 1.

One particular cell is occupied by the queen bee.
For a positive real number L, let B(L) count the cells with distance L from the queen bee cell (all distances are measured from centre to centre); you may assume that the honeycomb is large enough to accommodate for any distance we wish to consider.
For example, B(√3)=6, B(√21)=12 and B(111111111)=54.
Find the number of L≤5×1011 such that B(L)=450.