1085773domain: NAppears in sequencesA sequence a(n) such that a(n+1)^2 - a(n)^2 are perfect squares.at n=10A180313Numbers k = p1^e1*p2^e2, with e1 != e2, such that the Euclidean distance between points (p1, e1) and (p2, e2) is an integer.at n=25A387172