a(n) = Product_{k=1..n} lcm(n,k) / (k * gcd(n,k)).

Terms

a(0) =1a(1) =1a(2) =3a(3) =4a(4) =125a(5) =9a(6) =16807a(7) =1024a(8) =59049a(9) =15625a(10) =2357947691a(11) =5184a(13) =282475249a(14) =474609375a(15) =17179869184a(17) =3486784401a(19) =250000000000