Numbers that are the product of an odd number of distinct primes.

Terms

a(0) =2a(1) =3a(2) =5a(3) =7a(4) =11a(5) =13a(6) =17a(7) =19a(8) =23a(9) =29a(10) =30a(11) =31a(12) =37a(13) =41a(14) =42a(15) =43a(16) =47a(17) =53a(18) =59a(19) =61a(20) =66a(21) =67a(22) =70a(23) =71a(24) =73a(25) =78a(26) =79a(27) =83a(28) =89a(29) =97