Numbers k such that k and k^2 use only the digits 0, 1, 5, 6 and 8.

Terms

a(0) =0a(1) =1a(2) =10a(3) =81a(4) =100a(5) =810a(6) =816a(7) =1000a(8) =1081a(9) =8100a(10) =8160a(11) =10000a(12) =10801a(13) =10810a(14) =81000a(15) =81551a(16) =81600a(17) =81651a(18) =100000a(19) =108010a(20) =108100a(21) =810000a(22) =815510a(23) =815881a(24) =816000a(25) =816510a(26) =1000000a(27) =1008001a(28) =1008051a(29) =1080100