112 Lattice points
Appendix: The floor and the ceiling
Thefloorof a real numberxis the greatest integer not exceedingx:^1
x:= max{n∈Z:n≤x}.
On the other hand, theceilingofxis the least integer not exceeded
byx:
x:= min{n∈Z:n≥x}.
Ifxis not a half-integer, we denote by{x}the integernearestx.
Project
Find all integersnfor which
√
ndividesn.
How about√
ndividingn?(^1) It is sometimes called the greatest integer function ofxand denoted by[x].