Numbers k such that k and k^2 use only the digits 0, 3, 5, 7 and 9.

Terms

a(0) =0a(1) =3a(2) =30a(3) =300a(4) =3000a(5) =5753a(6) =9503a(7) =30000a(8) =57530a(9) =75503a(10) =95030a(11) =300000a(12) =550503a(13) =575300a(14) =755030a(15) =950300a(16) =995003a(17) =3000000a(18) =5505030a(19) =5753000a(20) =7550300a(21) =9503000a(22) =9950030a(23) =30000000a(24) =30909503a(25) =55050300a(26) =57530000a(27) =73073753a(28) =75503000a(29) =95030000