Numbers whose base-3 digits are all present among their base-4 digits.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =13a(5) =18a(6) =22a(7) =24a(8) =25a(9) =26a(10) =28a(11) =33a(12) =36a(13) =41a(14) =56a(15) =66a(16) =70a(17) =72a(18) =73a(19) =74a(20) =75a(21) =78a(22) =81a(23) =82a(24) =84a(25) =88a(26) =96a(27) =97a(28) =98a(29) =99