Numbers whose decimal expansion contains only 0's and 2's.

Terms

a(0) =0a(1) =2a(2) =20a(3) =22a(4) =200a(5) =202a(6) =220a(7) =222a(8) =2000a(9) =2002a(10) =2020a(11) =2022a(12) =2200a(13) =2202a(14) =2220a(15) =2222a(16) =20000a(17) =20002a(18) =20020a(19) =20022a(20) =20200a(21) =20202a(22) =20220a(23) =20222a(24) =22000a(25) =22002a(26) =22020a(27) =22022a(28) =22200a(29) =22202