Numbers whose base-4 representation contains exactly four 1's and four 2's.

Terms

a(0) =21930a(1) =22122a(2) =22170a(3) =22182a(4) =22185a(5) =22890a(6) =22938a(7) =22950a(8) =22953a(9) =23130a(10) =23142a(11) =23145a(12) =23190a(13) =23193a(14) =23205a(15) =25962a(16) =26010a(17) =26022a(18) =26025a(19) =26202a(20) =26214a(21) =26217a(22) =26262a(23) =26265a(24) =26277a(25) =26970a(26) =26982a(27) =26985a(28) =27030a(29) =27033