36324domain: NAppears in sequencesa(n) is the concatenation of n and 9n.at n=35A009474Numbers k such that Sum_{i=1..k} gcd(k,i) divides Sum_{i=1..k} lcm(k,i).at n=13A072109Number of right triangles on a (n+1)X6 grid.at n=28A189810