Numbers k such that k and k^2 use only the digits 1, 3, 6, 7 and 9.

Terms

a(0) =1a(1) =3a(2) =6a(3) =13a(4) =19a(5) =31a(6) =37a(7) =63a(8) =131a(9) =313a(10) =363a(11) =369a(12) =796a(13) =1319a(14) =3376a(15) =11731a(16) =11736a(17) =17796a(18) =31131a(19) =31619a(20) =61131a(21) =61613a(22) =61637a(23) =117131a(24) =133937a(25) =191363a(26) =193176a(27) =311637a(28) =311736a(29) =333736