Numbers k such that k and k^2 use only the digits 0, 3, 4, 6 and 7.

Terms

a(0) =0a(1) =6a(2) =60a(3) =600a(4) =6000a(5) =60000a(6) =66076a(7) =600000a(8) =660760a(9) =6000000a(10) =6607600a(11) =60000000a(12) =60003706a(13) =60036706a(14) =66036076a(15) =66066376a(16) =66076000a(17) =600000000a(18) =600037060a(19) =600306344a(20) =600367060a(21) =600373006a(22) =606336074a(23) =660360760a(24) =660663760a(25) =660760000a(26) =660760474a(27) =6000000000a(28) =6000036706a(29) =6000370600