a(n) = position of n in A026236.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =7a(5) =5a(6) =6a(7) =16a(8) =8a(9) =9a(10) =31a(11) =10a(12) =41a(13) =48a(14) =11a(15) =12a(16) =63a(17) =72a(18) =13a(19) =84a(20) =14a(21) =15a(22) =105a(23) =17a(24) =115a(25) =126a(26) =18a(27) =140a(28) =151a(29) =19