Numbers k such that k and k^2 use only the digits 0, 1, 4 and 8.

Terms

a(0) =0a(1) =1a(2) =10a(3) =100a(4) =1000a(5) =10000a(6) =10401a(7) =100000a(8) =104010a(9) =1000000a(10) =1004001a(11) =1040100a(12) =10000000a(13) =10040010a(14) =10401000a(15) =100000000a(16) =100040001a(17) =100400100a(18) =104010000a(19) =1000000000a(20) =1000400010a(21) =1004001000a(22) =1040100000a(23) =10000000000a(24) =10000400001a(25) =10004000100a(26) =10040010000a(27) =10401000000a(28) =100000000000a(29) =100004000010