Numbers having period-2 4-digitized sequences.

Terms

a(0) =66a(1) =127a(2) =172a(3) =217a(4) =228a(5) =271a(6) =282a(7) =445a(8) =454a(9) =456a(10) =465a(11) =544a(12) =546a(13) =564a(14) =606a(15) =645a(16) =654a(17) =660a(18) =712a(19) =721a(20) =822a(21) =1027a(22) =1072a(23) =1137a(24) =1149a(25) =1173a(26) =1188a(27) =1194a(28) =1207a(29) =1248