a(n) = (1/2)*(s(n) + 1), where s(n) is the n-th odd number in A026255.

Terms

a(0) =1a(1) =2a(2) =4a(3) =5a(4) =3a(5) =6a(6) =11a(7) =12a(8) =7a(9) =8a(10) =9a(11) =17a(12) =18a(13) =10a(14) =19a(15) =24a(16) =13a(17) =25a(18) =14a(19) =15a(20) =16a(21) =30a(22) =31a(23) =32a(24) =37a(25) =20a(26) =38a(27) =21a(28) =22a(29) =23