What is the sidelength of the smallest square in which one can fit $n$ non-overlapping squares of sidelengths $1,2,3,4,...,n$ ?
And what is the sidelength of the smallest cube in which one can fit $n$ non-intersecting cubes of sidelengths $1,2,3,4,...,n$ ?
All squares/cubes have all sides paralell, no rotation