a(n) = Product_{d|n} (d*sigma(d)) where sigma(k) = the sum of the divisors of k (A000203).

Terms

a(0) =1a(1) =6a(2) =12a(3) =168a(4) =30a(5) =5184a(6) =56a(7) =20160a(8) =1404a(9) =32400a(10) =132a(11) =48771072a(12) =182a(13) =112896a(14) =129600a(15) =9999360a(16) =306a(17) =425782656a(18) =380a(19) =762048000a(20) =451584a(21) =627264a(22) =552a(24) =23250a(25) =1192464a(26) =1516320a(27) =4956585984a(28) =870a(30) =992a(31) =20158709760