63921domain: NAppears in sequencesa(n) = (n - 1)*(n^2 + n - 1).at n=40A033445Number of subsets {x(1),x(2),...,x(k)} of {1,2,...,n} such that all differences |x(i)-x(j)| are distinct.at n=28A143823Composite squarefree integers for which the sum of the squares of their factors is a square.at n=37A379780