Palindromic odd numbers with exactly 2 prime factors (counted with multiplicity).

Terms

a(0) =9a(1) =33a(2) =55a(3) =77a(4) =111a(5) =121a(6) =141a(7) =161a(8) =303a(9) =323a(10) =393a(11) =505a(12) =515a(13) =535a(14) =545a(15) =565a(16) =707a(17) =717a(18) =737a(19) =767a(20) =939a(21) =949a(22) =959a(23) =979a(24) =989a(25) =1111a(26) =1441a(27) =1661a(28) =1991a(29) =3113