Numbers k such that k and k^2 use only the digits 0, 1, 2, 5 and 7.

Terms

a(0) =0a(1) =1a(2) =5a(3) =10a(4) =11a(5) =15a(6) =50a(7) =100a(8) =101a(9) =105a(10) =110a(11) =150a(12) =500a(13) =501a(14) =505a(15) =711a(16) =715a(17) =755a(18) =1000a(19) =1001a(20) =1005a(21) =1010a(22) =1011a(23) =1050a(24) =1100a(25) =1101a(26) =1105a(27) =1255a(28) =1500a(29) =5000