a(n) = (1/2)*s(n), where s = A026262.

Terms

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