a(n) = sigma(sigma(n))*sigma(n).

Terms

a(0) =1a(1) =12a(2) =28a(3) =56a(4) =72a(5) =336a(6) =120a(7) =360a(8) =182a(9) =702a(10) =336a(11) =1568a(12) =336a(13) =1440a(14) =1440a(15) =992a(16) =702a(17) =2184a(18) =840a(19) =4032a(20) =2016a(21) =3276a(22) =1440a(23) =10080a(24) =992a(25) =4032a(26) =3600a(27) =6720a(28) =2160a(29) =14040