Numbers with a single 1 in their ternary expansion.

Terms

a(0) =1a(1) =3a(2) =5a(3) =7a(4) =9a(5) =11a(6) =15a(7) =17a(8) =19a(9) =21a(10) =23a(11) =25a(12) =27a(13) =29a(14) =33a(15) =35a(16) =45a(17) =47a(18) =51a(19) =53a(20) =55a(21) =57a(22) =59a(23) =61a(24) =63a(25) =65a(26) =69a(27) =71a(28) =73a(29) =75