Numbers with at most 2 prime factors (counted with multiplicity).

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =5a(5) =6a(6) =7a(7) =9a(8) =10a(9) =11a(10) =13a(11) =14a(12) =15a(13) =17a(14) =19a(15) =21a(16) =22a(17) =23a(18) =25a(19) =26a(20) =29a(21) =31a(22) =33a(23) =34a(24) =35a(25) =37a(26) =38a(27) =39a(28) =41a(29) =43