Numbers in which 0,1,2,3 all occur in base 4.

Terms

a(0) =75a(1) =78a(2) =99a(3) =108a(4) =114a(5) =120a(6) =135a(7) =141a(8) =147a(9) =156a(10) =177a(11) =180a(12) =198a(13) =201a(14) =210a(15) =216a(16) =225a(17) =228a(18) =267a(19) =270a(20) =283a(21) =286a(22) =291a(23) =295a(24) =299a(25) =300a(26) =301a(27) =302a(28) =303a(29) =306