Numbers k such that k and k^2 use only the digits 0, 2, 5, 7 and 9.

Terms

a(0) =0a(1) =5a(2) =27a(3) =50a(4) =77a(5) =95a(6) =270a(7) =500a(8) =505a(9) =527a(10) =755a(11) =770a(12) =950a(13) =995a(14) =2700a(15) =2755a(16) =5000a(17) =5005a(18) =5027a(19) =5050a(20) =5077a(21) =5095a(22) =5205a(23) =5270a(24) =7227a(25) =7550a(26) =7700a(27) =9500a(28) =9950a(29) =9995