1, 3, 5 and the nonnegative even numbers.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =5a(6) =6a(7) =8a(8) =10a(9) =12a(10) =14a(11) =16a(12) =18a(13) =20a(14) =22a(15) =24a(16) =26a(17) =28a(18) =30a(19) =32a(20) =34a(21) =36a(22) =38a(23) =40a(24) =42a(25) =44a(26) =46a(27) =48a(28) =50a(29) =52