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

Terms

a(0) =0a(1) =3a(2) =30a(3) =300a(4) =3000a(5) =30000a(6) =300000a(7) =550503a(8) =3000000a(9) =5505030a(10) =30000000a(11) =55050300a(12) =300000000a(13) =550503000a(14) =3000000000a(15) =5505030000a(16) =30000000000a(17) =55050300000a(18) =300000000000a(19) =550500050003a(20) =550503000000