a(n) = smallest number m such that m*tau(m)/sigma(m) = n, or 0 if no such m exists.

Terms

a(0) =1a(1) =6a(2) =28a(3) =0a(4) =140a(5) =270a(6) =8128a(7) =672a(8) =1638a(9) =6200a(10) =2970a(11) =0a(12) =105664a(13) =18620a(14) =8190a(15) =0a(16) =27846a(17) =0a(18) =117800a(19) =0a(20) =55860a(21) =0a(22) =0a(23) =30240a(24) =173600a(25) =242060a(26) =167400a(27) =0a(28) =237510a(29) =0