Numbers k such that k and k^2 use only the digits 0, 2, 4, 6 and 8.

Terms

a(0) =0a(1) =2a(2) =8a(3) =20a(4) =22a(5) =68a(6) =80a(7) =200a(8) =202a(9) =220a(10) =262a(11) =668a(12) =680a(13) =800a(14) =2000a(15) =2002a(16) =2020a(17) =2022a(18) =2200a(19) =2202a(20) =2620a(21) =6668a(22) =6680a(23) =6800a(24) =8000a(25) =8262a(26) =20000a(27) =20002a(28) =20020a(29) =20022