Numbers k such that k and k^2 use only the digits 0, 1, 6, 7 and 8.

Terms

a(0) =0a(1) =1a(2) =10a(3) =100a(4) =881a(5) =1000a(6) =8776a(7) =8810a(8) =10000a(9) =10801a(10) =87760a(11) =88100a(12) =88776a(13) =100000a(14) =108010a(15) =877600a(16) =881000a(17) =887760a(18) =1000000a(19) =1008001a(20) =1077776a(21) =1080100a(22) =7866881a(23) =8776000a(24) =8810000a(25) =8877600a(26) =10000000a(27) =10080010a(28) =10777760a(29) =10801000