215136domain: NAppears in sequencesTotal number of line segments between points visible to each other in a square n X n lattice.at n=28A141255E.g.f.: Sum_{n>=0} a(n) * (cos(n*x)-sin(n*x)) * x^n/n! = 1 + x.at n=6A218798Number of n X 5 0..1 arrays with rows nondecreasing and antidiagonals unimodal.at n=7A224130