a(n) = the smallest number k such that Sum_{d|k} 1/tau(d) >= n.

Terms

a(0) =1a(1) =6a(2) =24a(3) =60a(4) =180a(5) =420a(6) =840a(7) =2520a(8) =4620a(9) =9240a(10) =13860a(11) =27720a(12) =55440a(13) =55440a(14) =110880a(15) =166320a(16) =180180a(17) =360360a(18) =360360a(19) =720720a(20) =720720a(21) =1441440a(22) =1801800a(23) =2162160a(24) =3063060a(25) =4084080a(26) =6126120a(27) =6126120a(28) =6126120a(29) =12252240