n, n^2 and n^3 all use only even digits.

Terms

a(0) =0a(1) =2a(2) =20a(3) =200a(4) =202a(5) =2000a(6) =2002a(7) =2020a(8) =20000a(9) =20002a(10) =20020a(11) =20200a(12) =200000a(13) =200002a(14) =200020a(15) =200200a(16) =202000a(17) =2000000a(18) =2000002a(19) =2000020a(20) =2000200a(21) =2002000a(22) =2020000a(23) =20000000a(24) =20000002a(25) =20000020a(26) =20000200a(27) =20000202a(28) =20002000a(29) =20002002