3-imperfect numbers.

Terms

a(0) =6a(1) =120a(2) =126a(3) =2520a(4) =2640a(5) =30240a(6) =32640a(7) =37800a(8) =37926a(9) =55440a(10) =685440a(11) =758520a(12) =831600a(13) =2600640a(14) =5533920a(15) =6917400a(16) =9102240a(17) =10281600a(18) =11377800a(19) =16687440a(20) =152182800a(21) =206317440a(22) =250311600a(23) =475917120a(24) =866829600a(25) =1665709920a(26) =1881532800a(27) =2082137400a(28) =2147450880