Numbers containing an odd number of letters.

Terms

a(0) =1a(1) =2a(2) =3a(3) =6a(4) =7a(5) =8a(6) =10a(7) =15a(8) =16a(9) =17a(10) =21a(11) =22a(12) =23a(13) =26a(14) =27a(15) =28a(16) =31a(17) =32a(18) =33a(19) =36a(20) =37a(21) =38a(22) =40a(23) =44a(24) =45a(25) =49a(26) =50a(27) =54a(28) =55a(29) =59