a(n) = sum_(d|n) ((product_(d|n) d) / d).

Terms

a(0) =1a(1) =3a(2) =4a(3) =14a(4) =6a(5) =72a(6) =8a(7) =120a(8) =39a(9) =180a(10) =12a(11) =4032a(12) =14a(13) =336a(14) =360a(15) =1984a(16) =18a(17) =12636a(18) =20a(19) =16800a(20) =672a(21) =792a(22) =24a(23) =829440a(24) =155a(25) =1092a(26) =1080a(27) =43904a(28) =30a(29) =1944000