Positions of even numbers in A004432.

Terms

a(0) =1a(1) =3a(2) =5a(3) =7a(4) =9a(5) =11a(6) =13a(7) =15a(8) =16a(9) =19a(10) =21a(11) =23a(12) =24a(13) =27a(14) =30a(15) =31a(16) =33a(17) =36a(18) =37a(19) =39a(20) =41a(21) =44a(22) =46a(23) =48a(24) =50a(25) =51a(26) =53a(27) =55a(28) =59a(29) =61