k-imperfect numbers for some k >= 1.

Terms

a(0) =1a(1) =2a(2) =6a(3) =12a(4) =40a(5) =120a(6) =126a(7) =252a(8) =880a(9) =2520a(10) =2640a(11) =10880a(12) =30240a(13) =32640a(14) =37800a(15) =37926a(16) =55440a(17) =75852a(18) =685440a(19) =758520a(20) =831600a(21) =2600640a(22) =5533920a(23) =6917400a(24) =9102240a(25) =10281600a(26) =11377800a(27) =16687440a(28) =152182800a(29) =206317440