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

Terms

a(0) =0a(1) =6a(2) =26a(3) =60a(4) =260a(5) =600a(6) =606a(7) =2600a(8) =6000a(9) =6006a(10) =6060a(11) =26000a(12) =60000a(13) =60006a(14) =60060a(15) =60600a(16) =260000a(17) =270606a(18) =600000a(19) =600006a(20) =600060a(21) =600600a(22) =606000a(23) =2600000a(24) =2603326a(25) =2706060a(26) =6000000a(27) =6000006a(28) =6000060a(29) =6000600