Numbers k such that k and k^2 use only the digits 1, 2, 6, 8 and 9.

Terms

a(0) =1a(1) =9a(2) =11a(3) =91a(4) =96a(5) =261a(6) =911a(7) =1291a(8) =1619a(9) =2986a(10) =16989a(11) =26291a(12) =81619a(13) =92896a(14) =126969a(15) =128891a(16) =162161a(17) =298161a(18) =928881a(19) =2861291a(20) =16162296a(21) =16988869a(22) =26289291a(23) =28616119a(24) =29696296a(25) =81669261a(26) =82866881a(27) =92888219a(28) =129196989a(29) =129221619