Numbers k such that k and k^2 use only the digits 0, 3, 7, 8 and 9.

Terms

a(0) =0a(1) =3a(2) =30a(3) =300a(4) =3000a(5) =30000a(6) =300000a(7) =989803a(8) =3000000a(9) =8370783a(10) =9889783a(11) =9898030a(12) =30000000a(13) =83707830a(14) =88830783a(15) =89330333a(16) =89380833a(17) =89909833a(18) =93803033a(19) =98897830a(20) =98980300a(21) =300000000a(22) =837078300a(23) =878003303a(24) =888307830a(25) =893303330a(26) =893808330a(27) =893889803a(28) =899098330a(29) =938030330