Numbers whose base-9 representation has the same number of 1's and 4's.

Terms

a(0) =0a(1) =2a(2) =3a(3) =5a(4) =6a(5) =7a(6) =8a(7) =13a(8) =18a(9) =20a(10) =21a(11) =23a(12) =24a(13) =25a(14) =26a(15) =27a(16) =29a(17) =30a(18) =32a(19) =33a(20) =34a(21) =35a(22) =37a(23) =45a(24) =47a(25) =48a(26) =50a(27) =51a(28) =52a(29) =53