Numbers k such that k and k^2 use only the digits 1, 2, 4, 8 and 9.

Terms

a(0) =1a(1) =2a(2) =9a(3) =11a(4) =12a(5) =21a(6) =22a(7) =29a(8) =91a(9) =122a(10) =141a(11) =212a(12) =221a(13) =222a(14) =288a(15) =441a(16) =911a(17) =921a(18) =1118a(19) =1191a(20) =1488a(21) =2212a(22) =2988a(23) =11141a(24) =11882a(25) =14829a(26) =21212a(27) =22229a(28) =42921a(29) =49441