Numbers whose base-3 representation is the juxtaposition of two identical strings.

Terms

a(0) =4a(1) =8a(2) =30a(3) =40a(4) =50a(5) =60a(6) =70a(7) =80a(8) =252a(9) =280a(10) =308a(11) =336a(12) =364a(13) =392a(14) =420a(15) =448a(16) =476a(17) =504a(18) =532a(19) =560a(20) =588a(21) =616a(22) =644a(23) =672a(24) =700a(25) =728a(26) =2214a(27) =2296a(28) =2378a(29) =2460