Numbers k such that k and k^2 use only the digits 0, 1, 4 and 5.

Terms

a(0) =0a(1) =1a(2) =10a(3) =100a(4) =1000a(5) =10000a(6) =100000a(7) =100501a(8) =1000000a(9) =1005010a(10) =10000000a(11) =10005001a(12) =10050100a(13) =100000000a(14) =100050010a(15) =100501000a(16) =1000000000a(17) =1000050001a(18) =1000500100a(19) =1005010000a(20) =10000000000a(21) =10000500010a(22) =10005001000a(23) =10050100000a(24) =100000000000a(25) =100000500001a(26) =100005000100a(27) =100050010000a(28) =100501000000a(29) =1000000000000