Numbers whose base-10 representation has the same number of 1's and 9's.

Terms

a(0) =0a(1) =2a(2) =3a(3) =4a(4) =5a(5) =6a(6) =7a(7) =8a(8) =19a(9) =20a(10) =22a(11) =23a(12) =24a(13) =25a(14) =26a(15) =27a(16) =28a(17) =30a(18) =32a(19) =33a(20) =34a(21) =35a(22) =36a(23) =37a(24) =38a(25) =40a(26) =42a(27) =43a(28) =44a(29) =45