Numbers k such that 2^k does not contain the digit 9 (probably finite).

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =5a(6) =6a(7) =7a(8) =8a(9) =9a(10) =10a(11) =11a(12) =14a(13) =15a(14) =16a(15) =17a(16) =18a(17) =19a(18) =20a(19) =23a(20) =24a(21) =25a(22) =26a(23) =27a(24) =28a(25) =30a(26) =31a(27) =45a(28) =46a(29) =47