Numbers k such that k and k^2 use only the digits 0, 1, 4, 7 and 8.

Terms

a(0) =0a(1) =1a(2) =10a(3) =88a(4) =100a(5) =878a(6) =880a(7) =1000a(8) =1071a(9) =4141a(10) =8780a(11) =8800a(12) =8878a(13) =10000a(14) =10401a(15) =10710a(16) =41410a(17) =87800a(18) =88000a(19) =88780a(20) =100000a(21) =104010a(22) =107100a(23) =108848a(24) =414100a(25) =878000a(26) =880000a(27) =887800a(28) =1000000a(29) =1004001