Positions of odd numbers in A003136.

Terms

a(0) =2a(1) =3a(2) =5a(3) =6a(4) =8a(5) =10a(6) =11a(7) =12a(8) =13a(9) =15a(10) =17a(11) =18a(12) =19a(13) =21a(14) =23a(15) =24a(16) =25a(17) =27a(18) =28a(19) =29a(20) =31a(21) =32a(22) =34a(23) =35a(24) =36a(25) =38a(26) =40a(27) =41a(28) =43a(29) =44