A 2 by X rectangle can obviously have 2*X circles of diameter 1 placed inside it without overlapping. What is the smallest integer X where a 2 by X box can have 2*X+1 non-overlapping circles placed inside it?
I have played with this, and have not figured out how to fit more than 2*X circles in. Hexagonal packing in a 2 by X rectangle seems to me to be less dense. I will be very interested in the solution