Numbers k such that k and k^2 use only the digits 0, 1, 2 and 4.

Terms

a(0) =0a(1) =1a(2) =2a(3) =10a(4) =11a(5) =12a(6) =20a(7) =21a(8) =100a(9) =101a(10) =102a(11) =110a(12) =120a(13) =200a(14) =201a(15) =210a(16) =1000a(17) =1001a(18) =1002a(19) =1010a(20) =1011a(21) =1012a(22) =1020a(23) =1021a(24) =1100a(25) =1101a(26) =1102a(27) =1200a(28) =1201a(29) =2000