Numbers that have all their divisors in A002191 (possible values for sigma(n), A000203).

Terms

a(0) =1a(1) =3a(2) =7a(3) =13a(4) =31a(5) =39a(6) =91a(7) =93a(8) =127a(9) =217a(10) =307a(11) =381a(12) =403a(13) =921a(14) =961a(15) =1093a(16) =1209a(17) =1651a(18) =1723a(19) =2149a(20) =2801a(21) =2821a(22) =3279a(23) =3541a(24) =3937a(25) =3991a(26) =4953a(27) =5113a(28) =5169a(29) =7651