0 together with odd numbers.

Terms

a(0) =0a(1) =1a(2) =3a(3) =5a(4) =7a(5) =9a(6) =11a(7) =13a(8) =15a(9) =17a(10) =19a(11) =21a(12) =23a(13) =25a(14) =27a(15) =29a(16) =31a(17) =33a(18) =35a(19) =37a(20) =39a(21) =41a(22) =43a(23) =45a(24) =47a(25) =49a(26) =51a(27) =53a(28) =55a(29) =57