Numbers whose base-4 representation contains no 1's and exactly four 3's.

Terms

a(0) =255a(1) =767a(2) =831a(3) =959a(4) =975a(5) =1007a(6) =1011a(7) =1019a(8) =1020a(9) =1022a(10) =2303a(11) =2815a(12) =2879a(13) =3007a(14) =3023a(15) =3055a(16) =3059a(17) =3067a(18) =3068a(19) =3070a(20) =3135a(21) =3263a(22) =3279a(23) =3311a(24) =3315a(25) =3323a(26) =3324a(27) =3326a(28) =3647a(29) =3775