Numbers that are sparsely totient (A036913) and of least prime signature (A025487).

Terms

a(0) =2a(1) =6a(2) =12a(3) =30a(4) =60a(5) =120a(6) =210a(7) =240a(8) =420a(9) =840a(10) =1260a(11) =1680a(12) =2310a(13) =4620a(14) =9240a(15) =13860a(16) =18480a(17) =30030a(18) =60060a(19) =120120a(20) =180180a(21) =240240a(22) =360360a(23) =510510a(24) =1021020a(25) =2042040a(26) =3063060a(27) =4084080a(28) =6126120a(29) =8168160