a(n) = position of n in A026194.

Terms

a(0) =1a(1) =2a(2) =3a(3) =9a(4) =4a(5) =5a(6) =15a(7) =6a(8) =7a(9) =21a(10) =8a(11) =25a(12) =27a(13) =10a(14) =11a(15) =33a(16) =12a(17) =13a(18) =39a(19) =14a(20) =43a(21) =45a(22) =16a(23) =17a(24) =51a(25) =18a(26) =19a(27) =57a(28) =20a(29) =61