Aliquot sequence starting at 840 (reaches 1 at 747th term).

Terms

a(0) =840a(1) =2040a(2) =4440a(3) =9240a(4) =25320a(5) =51000a(6) =117480a(7) =271320a(8) =765480a(9) =1531320a(10) =3721800a(11) =7817640a(12) =15635640a(13) =32899560a(14) =65799480a(15) =139098120a(16) =349027320a(17) =699333000a(18) =1597611000a(19) =3386944680a(20) =9543610200a(21) =20041583280